diff --git a/internal/middleware/limitrate/limitrate_test.go b/internal/middleware/limitrate/limitrate_test.go
new file mode 100644
index 0000000..687b699
--- /dev/null
+++ b/internal/middleware/limitrate/limitrate_test.go
@@ -0,0 +1,609 @@
+// Package limitrate 提供响应速率限制中间件的测试。
+//
+// 该文件测试速率限制模块的各项功能，包括：
+//   - 中间件创建和名称
+//   - 限速写入器创建
+//   - 令牌桶算法
+//   - 零值和负值边界情况
+//   - 并发安全性
+//
+// 作者：xfy
+package limitrate
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/valyala/fasthttp"
+	"rua.plus/lolly/internal/config"
+	"rua.plus/lolly/internal/testutil"
+)
+
+// TestConstants 测试常量值。
+func TestConstants(t *testing.T) {
+	if LargeFileStrategySkip != "skip" {
+		t.Errorf("LargeFileStrategySkip = %q, want %q", LargeFileStrategySkip, "skip")
+	}
+	if LargeFileStrategyCoarse != "coarse" {
+		t.Errorf("LargeFileStrategyCoarse = %q, want %q", LargeFileStrategyCoarse, "coarse")
+	}
+}
+
+// TestNewMiddleware 测试创建中间件。
+func TestNewMiddleware(t *testing.T) {
+	tests := []struct {
+		name string
+		cfg  *config.LimitRateConfig
+	}{
+		{
+			name: "nil config",
+			cfg:  nil,
+		},
+		{
+			name: "valid config",
+			cfg: &config.LimitRateConfig{
+				Rate:  1024,
+				Burst: 2048,
+			},
+		},
+		{
+			name: "zero rate",
+			cfg: &config.LimitRateConfig{
+				Rate:  0,
+				Burst: 1024,
+			},
+		},
+		{
+			name: "negative rate",
+			cfg: &config.LimitRateConfig{
+				Rate:  -1,
+				Burst: 1024,
+			},
+		},
+		{
+			name: "zero burst",
+			cfg: &config.LimitRateConfig{
+				Rate:  1024,
+				Burst: 0,
+			},
+		},
+		{
+			name: "with large file config",
+			cfg: &config.LimitRateConfig{
+				Rate:               1024,
+				Burst:              2048,
+				LargeFileThreshold: 10 * 1024 * 1024,
+				LargeFileStrategy:  LargeFileStrategySkip,
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			mw := NewMiddleware(tt.cfg)
+			if mw == nil {
+				t.Error("NewMiddleware() returned nil")
+			}
+		})
+	}
+}
+
+// TestMiddleware_Name 测试中间件名称。
+func TestMiddleware_Name(t *testing.T) {
+	mw := NewMiddleware(nil)
+	if mw.Name() != "limit_rate" {
+		t.Errorf("Name() = %q, want %q", mw.Name(), "limit_rate")
+	}
+}
+
+// TestMiddleware_Process_NilConfig 测试空配置时的处理。
+func TestMiddleware_Process_NilConfig(t *testing.T) {
+	mw := NewMiddleware(nil)
+
+	called := false
+	nextHandler := func(ctx *fasthttp.RequestCtx) {
+		called = true
+		ctx.SetStatusCode(fasthttp.StatusOK)
+	}
+
+	handler := mw.Process(nextHandler)
+	if handler == nil {
+		t.Fatal("Process() returned nil handler")
+	}
+
+	ctx := testutil.NewRequestCtx("GET", "/test")
+	handler(ctx)
+
+	if !called {
+		t.Error("next handler was not called")
+	}
+	if ctx.Response.StatusCode() != fasthttp.StatusOK {
+		t.Errorf("status code = %d, want %d", ctx.Response.StatusCode(), fasthttp.StatusOK)
+	}
+}
+
+// TestMiddleware_Process_ZeroRate 测试零速率时的处理。
+func TestMiddleware_Process_ZeroRate(t *testing.T) {
+	mw := NewMiddleware(&config.LimitRateConfig{
+		Rate:  0,
+		Burst: 1024,
+	})
+
+	called := false
+	nextHandler := func(ctx *fasthttp.RequestCtx) {
+		called = true
+		ctx.SetStatusCode(fasthttp.StatusOK)
+	}
+
+	handler := mw.Process(nextHandler)
+	if handler == nil {
+		t.Fatal("Process() returned nil handler")
+	}
+
+	ctx := testutil.NewRequestCtx("GET", "/test")
+	handler(ctx)
+
+	if !called {
+		t.Error("next handler was not called")
+	}
+}
+
+// TestMiddleware_Process_NegativeRate 测试负速率时的处理。
+func TestMiddleware_Process_NegativeRate(t *testing.T) {
+	mw := NewMiddleware(&config.LimitRateConfig{
+		Rate:  -100,
+		Burst: 1024,
+	})
+
+	called := false
+	nextHandler := func(ctx *fasthttp.RequestCtx) {
+		called = true
+		ctx.SetStatusCode(fasthttp.StatusOK)
+	}
+
+	handler := mw.Process(nextHandler)
+	ctx := testutil.NewRequestCtx("GET", "/test")
+	handler(ctx)
+
+	if !called {
+		t.Error("next handler was not called")
+	}
+}
+
+// TestMiddleware_Process_ValidConfig 测试有效配置时的处理。
+func TestMiddleware_Process_ValidConfig(t *testing.T) {
+	mw := NewMiddleware(&config.LimitRateConfig{
+		Rate:  1024,
+		Burst: 2048,
+	})
+
+	called := false
+	nextHandler := func(ctx *fasthttp.RequestCtx) {
+		called = true
+		ctx.SetStatusCode(fasthttp.StatusOK)
+	}
+
+	handler := mw.Process(nextHandler)
+	ctx := testutil.NewRequestCtx("GET", "/test")
+	handler(ctx)
+
+	if !called {
+		t.Error("next handler was not called")
+	}
+}
+
+// TestNewRateLimitedWriter 测试创建限速写入器。
+func TestNewRateLimitedWriter(t *testing.T) {
+	buf := &bytes.Buffer{}
+
+	tests := []struct {
+		name  string
+		rate  int64
+		burst int64
+	}{
+		{"positive rate and burst", 1024, 2048},
+		{"zero rate", 0, 1024},
+		{"negative rate", -1, 1024},
+		{"zero burst", 1024, 0},
+		{"negative burst", 1024, -1},
+		{"rate equals burst", 1024, 1024},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			w := NewRateLimitedWriter(buf, tt.rate, tt.burst)
+			if w == nil {
+				t.Error("NewRateLimitedWriter() returned nil")
+			}
+			if w.rate != tt.rate {
+				t.Errorf("rate = %d, want %d", w.rate, tt.rate)
+			}
+			if w.maxBucket != tt.burst {
+				t.Errorf("maxBucket = %d, want %d", w.maxBucket, tt.burst)
+			}
+		})
+	}
+}
+
+// TestRateLimitedWriter_Write_ZeroRate 测试零速率时直接写入。
+func TestRateLimitedWriter_Write_ZeroRate(t *testing.T) {
+	buf := &bytes.Buffer{}
+	w := NewRateLimitedWriter(buf, 0, 1024)
+
+	data := []byte("hello world")
+	n, err := w.Write(data)
+	if err != nil {
+		t.Errorf("Write() error = %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write() n = %d, want %d", n, len(data))
+	}
+	if !bytes.Equal(buf.Bytes(), data) {
+		t.Errorf("buffer = %q, want %q", buf.Bytes(), data)
+	}
+}
+
+// TestRateLimitedWriter_Write_NegativeRate 测试负速率时直接写入。
+func TestRateLimitedWriter_Write_NegativeRate(t *testing.T) {
+	buf := &bytes.Buffer{}
+	w := NewRateLimitedWriter(buf, -1, 1024)
+
+	data := []byte("hello world")
+	n, err := w.Write(data)
+	if err != nil {
+		t.Errorf("Write() error = %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write() n = %d, want %d", n, len(data))
+	}
+}
+
+// TestRateLimitedWriter_Write_WithinBucket 测试令牌充足时的写入。
+func TestRateLimitedWriter_Write_WithinBucket(t *testing.T) {
+	buf := &bytes.Buffer{}
+	rate := int64(1024)
+	burst := int64(2048)
+	w := NewRateLimitedWriter(buf, rate, burst)
+
+	data := []byte("hello")
+	n, err := w.Write(data)
+	if err != nil {
+		t.Errorf("Write() error = %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write() n = %d, want %d", n, len(data))
+	}
+
+	// 验证令牌被消耗
+	expectedBucket := burst - int64(len(data))
+	if w.bucket != expectedBucket {
+		t.Errorf("bucket = %d, want %d", w.bucket, expectedBucket)
+	}
+}
+
+// TestRateLimitedWriter_Write_ExceedsBucket 测试令牌不足时的分批写入。
+func TestRateLimitedWriter_Write_ExceedsBucket(t *testing.T) {
+	buf := &bytes.Buffer{}
+	rate := int64(100) // 100 bytes/sec
+	burst := int64(10) // only 10 tokens initially
+	w := NewRateLimitedWriter(buf, rate, burst)
+
+	// 写入超过 burst 的数据
+	data := make([]byte, 50)
+	for i := range data {
+		data[i] = 'a'
+	}
+
+	n, err := w.Write(data)
+	if err != nil {
+		t.Errorf("Write() error = %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write() n = %d, want %d", n, len(data))
+	}
+	if !bytes.Equal(buf.Bytes(), data) {
+		t.Error("buffer content mismatch")
+	}
+}
+
+// TestRateLimitedWriter_Write_Error 测试底层写入错误。
+func TestRateLimitedWriter_Write_Error(t *testing.T) {
+	errWriter := &errorWriter{err: errors.New("write error")}
+
+	// 测试零速率时的错误传播（零速率时直接调用底层 writer，错误会传播）
+	w := NewRateLimitedWriter(errWriter, 0, 1024)
+
+	data := []byte("hello")
+	_, err := w.Write(data)
+	if err == nil {
+		t.Error("Write() with zero rate should propagate error, got nil")
+	}
+
+	// 测试非零速率时的错误传播
+	w2 := NewRateLimitedWriter(errWriter, 1024, 10)
+	_, err = w2.Write(data)
+	if err == nil {
+		t.Error("Write() expected error, got nil")
+	}
+}
+
+// errorWriter 是一个总是返回错误的写入器。
+type errorWriter struct {
+	err error
+}
+
+func (w *errorWriter) Write(p []byte) (n int, err error) {
+	return 0, w.err
+}
+
+// TestRateLimitedWriter_Write_MultipleWrites 测试多次写入。
+func TestRateLimitedWriter_Write_MultipleWrites(t *testing.T) {
+	buf := &bytes.Buffer{}
+	rate := int64(1000)
+	burst := int64(100)
+	w := NewRateLimitedWriter(buf, rate, burst)
+
+	// 第一次写入消耗令牌
+	data1 := []byte("first")
+	n1, err := w.Write(data1)
+	if err != nil || n1 != len(data1) {
+		t.Errorf("first Write() failed: n=%d, err=%v", n1, err)
+	}
+
+	// 第二次写入
+	data2 := []byte("second")
+	n2, err := w.Write(data2)
+	if err != nil || n2 != len(data2) {
+		t.Errorf("second Write() failed: n=%d, err=%v", n2, err)
+	}
+
+	expected := append(data1, data2...)
+	if !bytes.Equal(buf.Bytes(), expected) {
+		t.Errorf("buffer = %q, want %q", buf.Bytes(), expected)
+	}
+}
+
+// TestRateLimitedWriter_BucketRefill 测试令牌桶补充。
+func TestRateLimitedWriter_BucketRefill(t *testing.T) {
+	buf := &bytes.Buffer{}
+	rate := int64(1000) // 1000 tokens/sec
+	burst := int64(100)
+	w := NewRateLimitedWriter(buf, rate, burst)
+
+	// 消耗所有令牌
+	w.bucket = 0
+
+	// 等待一段时间让令牌补充
+	time.Sleep(20 * time.Millisecond)
+
+	// 写入数据，应该能获得新令牌
+	data := []byte("test")
+	n, err := w.Write(data)
+	if err != nil {
+		t.Errorf("Write() error = %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write() n = %d, want %d", n, len(data))
+	}
+}
+
+// TestRateLimitedWriter_BucketMax 测试令牌桶上限。
+func TestRateLimitedWriter_BucketMax(t *testing.T) {
+	buf := &bytes.Buffer{}
+	rate := int64(1000)
+	burst := int64(100)
+	w := NewRateLimitedWriter(buf, rate, burst)
+
+	// 设置 bucket 超过最大值
+	w.bucket = burst + 500
+
+	// 等待让时间流逝，触发令牌补充逻辑
+	time.Sleep(10 * time.Millisecond)
+
+	// 写入数据
+	data := []byte("test")
+	_, err := w.Write(data)
+	if err != nil {
+		t.Errorf("Write() error = %v", err)
+	}
+
+	// bucket 不应超过 maxBucket
+	if w.bucket > w.maxBucket {
+		t.Errorf("bucket = %d, should not exceed maxBucket = %d", w.bucket, w.maxBucket)
+	}
+}
+
+// TestRateLimitedWriter_Concurrent 测试并发写入安全性。
+func TestRateLimitedWriter_Concurrent(t *testing.T) {
+	buf := &bytes.Buffer{}
+	rate := int64(10000) // 高速率以减少测试时间
+	burst := int64(1000)
+	w := NewRateLimitedWriter(buf, rate, burst)
+
+	var wg sync.WaitGroup
+	goroutines := 5
+	writesPerGoroutine := 10
+	data := []byte("test")
+
+	for i := 0; i < goroutines; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for j := 0; j < writesPerGoroutine; j++ {
+				_, _ = w.Write(data)
+			}
+		}()
+	}
+
+	wg.Wait()
+
+	expectedLen := goroutines * writesPerGoroutine * len(data)
+	if buf.Len() != expectedLen {
+		t.Errorf("buffer length = %d, want %d", buf.Len(), expectedLen)
+	}
+}
+
+// TestRateLimitedWriter_EmptyWrite 测试空写入。
+func TestRateLimitedWriter_EmptyWrite(t *testing.T) {
+	buf := &bytes.Buffer{}
+	w := NewRateLimitedWriter(buf, 1024, 100)
+
+	n, err := w.Write([]byte{})
+	if err != nil {
+		t.Errorf("Write() error = %v", err)
+	}
+	if n != 0 {
+		t.Errorf("Write() n = %d, want 0", n)
+	}
+}
+
+// TestRateLimitedWriter_LargeData 测试大数据写入。
+func TestRateLimitedWriter_LargeData(t *testing.T) {
+	buf := &bytes.Buffer{}
+	rate := int64(10000) // 10KB/s
+	burst := int64(1000) // 1KB burst
+	w := NewRateLimitedWriter(buf, rate, burst)
+
+	// 写入 5KB 数据
+	data := make([]byte, 5*1024)
+	for i := range data {
+		data[i] = byte(i % 256)
+	}
+
+	start := time.Now()
+	n, err := w.Write(data)
+	elapsed := time.Since(start)
+
+	if err != nil {
+		t.Errorf("Write() error = %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write() n = %d, want %d", n, len(data))
+	}
+
+	// 验证数据被正确写入
+	if !bytes.Equal(buf.Bytes(), data) {
+		t.Error("buffer content mismatch")
+	}
+
+	// 由于限速，写入时间应该大于零（令牌不足时需要等待）
+	t.Logf("Large data write took %v", elapsed)
+}
+
+// TestRateLimitedWriter_PartialWriteError 测试部分写入错误。
+func TestRateLimitedWriter_PartialWriteError(t *testing.T) {
+	// 创建一个写入部分数据后返回错误的 writer
+	partialWriter := &partialErrorWriter{maxWrite: 5}
+	w := NewRateLimitedWriter(partialWriter, 0, 100)
+
+	data := []byte("hello world")
+	n, err := w.Write(data)
+
+	// 零速率时，直接调用底层 writer
+	if err == nil {
+		t.Error("Write() expected error, got nil")
+	}
+	if n > len(data) {
+		t.Errorf("Write() n = %d, should not exceed %d", n, len(data))
+	}
+}
+
+// partialErrorWriter 写入 maxWrite 字节后返回错误。
+type partialErrorWriter struct {
+	maxWrite int
+}
+
+func (w *partialErrorWriter) Write(p []byte) (n int, err error) {
+	if len(p) <= w.maxWrite {
+		return len(p), nil
+	}
+	return w.maxWrite, errors.New("partial write error")
+}
+
+// TestRateLimitedWriter_TimeAdvancement 测试时间推进。
+func TestRateLimitedWriter_TimeAdvancement(t *testing.T) {
+	buf := &bytes.Buffer{}
+	rate := int64(1000)
+	burst := int64(100)
+	w := NewRateLimitedWriter(buf, rate, burst)
+
+	// 记录初始时间
+	initialTime := w.lastTime
+
+	// 写入一些数据
+	_, _ = w.Write([]byte("test"))
+
+	// lastTime 应该被更新
+	if !w.lastTime.After(initialTime) && w.lastTime != initialTime {
+		t.Error("lastTime should be updated after write")
+	}
+}
+
+// TestRateLimitedWriter_WriteAll 测试完整写入 io.Writer 接口兼容性。
+func TestRateLimitedWriter_WriteAll(t *testing.T) {
+	buf := &bytes.Buffer{}
+	w := NewRateLimitedWriter(buf, 1000, 100)
+
+	data := []byte("hello world, this is a test of the rate limited writer")
+
+	// 使用 io.Writer 接口
+	var writer io.Writer = w
+	n, err := writer.Write(data)
+	if err != nil {
+		t.Errorf("Write() error = %v", err)
+	}
+	if n != len(data) {
+		t.Errorf("Write() n = %d, want %d", n, len(data))
+	}
+}
+
+// BenchmarkMiddleware_Process 基准测试中间件处理。
+func BenchmarkMiddleware_Process(b *testing.B) {
+	mw := NewMiddleware(&config.LimitRateConfig{
+		Rate:  1024 * 1024, // 1MB/s
+		Burst: 2 * 1024 * 1024,
+	})
+
+	nextHandler := func(ctx *fasthttp.RequestCtx) {
+		ctx.SetStatusCode(fasthttp.StatusOK)
+	}
+
+	handler := mw.Process(nextHandler)
+	ctx := testutil.NewRequestCtx("GET", "/test")
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		handler(ctx)
+	}
+}
+
+// BenchmarkRateLimitedWriter_Write 基准测试限速写入。
+func BenchmarkRateLimitedWriter_Write(b *testing.B) {
+	buf := &bytes.Buffer{}
+	w := NewRateLimitedWriter(buf, 1024*1024, 1024*1024) // 高速率减少等待
+	data := make([]byte, 1024)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		buf.Reset()
+		w.bucket = w.maxBucket // 重置令牌桶
+		_, _ = w.Write(data)
+	}
+}
+
+// BenchmarkRateLimitedWriter_Concurrent 基准测试并发写入。
+func BenchmarkRateLimitedWriter_Concurrent(b *testing.B) {
+	buf := &bytes.Buffer{}
+	w := NewRateLimitedWriter(buf, 10*1024*1024, 1024*1024)
+	data := []byte("test data for benchmarking")
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			_, _ = w.Write(data)
+		}
+	})
+}