diff --git a/Makefile b/Makefile
index 4f84806..a86719a 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ COCO_INCLUDE ?= $(COCO_DIR)/include
 COCO_LIB     ?= $(COCO_DIR)/build
 
 CC = gcc
-CFLAGS = -Wall -Wextra -O2 -std=c11 -I$(COCO_INCLUDE)
+CFLAGS = -Wall -Wextra -O2 -std=c11 -D_GNU_SOURCE -I$(COCO_INCLUDE)
 LDFLAGS = -L$(COCO_LIB) -lcoco -lpthread -lm -luring -lz
 
 # 调试模式
@@ -20,7 +20,7 @@ PREFIX ?= /usr/local
 BINDIR = $(PREFIX)/bin
 
 # 源文件
-SRCS = main.c server.c http.c static.c log.c config.c
+SRCS = main.c server.c http.c static.c log.c config.c multipart.c
 OBJS = $(SRCS:.c=.o)
 TARGET = cocoon
 
@@ -78,17 +78,20 @@ unit-test: $(UNIT_TEST_BINS)
 	fi
 
 # 单元测试编译规则
+$(UNIT_TEST_DIR)/test_multipart: $(UNIT_TEST_DIR)/test_multipart.c multipart.c $(UNITY_SRC)
+	$(CC) $(CFLAGS) -I. -I$(UNIT_TEST_DIR)/../unity -o $@ $(UNIT_TEST_DIR)/test_multipart.c multipart.c $(UNITY_SRC) -lm
+
 $(UNIT_TEST_DIR)/test_http: $(UNIT_TEST_DIR)/test_http.c http.c log.c $(UNITY_SRC)
-	$(CC) $(CFLAGS) -D_GNU_SOURCE -I. -I$(UNIT_TEST_DIR)/../unity -o $@ $(UNIT_TEST_DIR)/test_http.c http.c log.c $(UNITY_SRC) -lm
+	$(CC) $(CFLAGS) -I. -I$(UNIT_TEST_DIR)/../unity -o $@ $(UNIT_TEST_DIR)/test_http.c http.c log.c $(UNITY_SRC) -lm
 
 $(UNIT_TEST_DIR)/test_static: $(UNIT_TEST_DIR)/test_static.c http.c log.c $(UNITY_SRC)
-	$(CC) $(CFLAGS) -D_GNU_SOURCE -I. -I$(UNIT_TEST_DIR)/../unity -o $@ $(UNIT_TEST_DIR)/test_static.c http.c log.c $(UNITY_SRC) -lm -lz
+	$(CC) $(CFLAGS) -I. -I$(UNIT_TEST_DIR)/../unity -o $@ $(UNIT_TEST_DIR)/test_static.c http.c log.c $(UNITY_SRC) -lm -lz
 
 $(UNIT_TEST_DIR)/test_log: $(UNIT_TEST_DIR)/test_log.c log.c $(UNITY_SRC)
-	$(CC) $(CFLAGS) -D_GNU_SOURCE -I. -I$(UNIT_TEST_DIR)/../unity -o $@ $(UNIT_TEST_DIR)/test_log.c log.c $(UNITY_SRC) -lm
+	$(CC) $(CFLAGS) -I. -I$(UNIT_TEST_DIR)/../unity -o $@ $(UNIT_TEST_DIR)/test_log.c log.c $(UNITY_SRC) -lm
 
 $(UNIT_TEST_DIR)/test_config: $(UNIT_TEST_DIR)/test_config.c config.c log.c $(UNITY_SRC)
-	$(CC) $(CFLAGS) -D_GNU_SOURCE -I. -I$(UNIT_TEST_DIR)/../unity -o $@ $(UNIT_TEST_DIR)/test_config.c config.c log.c $(UNITY_SRC) -lm
+	$(CC) $(CFLAGS) -I. -I$(UNIT_TEST_DIR)/../unity -o $@ $(UNIT_TEST_DIR)/test_config.c config.c log.c $(UNITY_SRC) -lm
 
 # 编译规则
 %.o: %.c
diff --git a/config.c b/config.c
index 170e4e7..af8c131 100644
--- a/config.c
+++ b/config.c
@@ -1,4 +1,3 @@
-#define _GNU_SOURCE
 
 /**
  * config.c - JSON 配置文件解析实现
diff --git a/http.c b/http.c
index 226b75b..9fad846 100644
--- a/http.c
+++ b/http.c
@@ -1,4 +1,3 @@
-#define _GNU_SOURCE
 
 /**
  * http.c - HTTP 解析与响应构建
diff --git a/server.c b/server.c
index 38b1bd4..af3b924 100644
--- a/server.c
+++ b/server.c
@@ -1,7 +1,4 @@
-#define _GNU_SOURCE
-
 /**
- * server.c - 服务器核心实现
  *
  * 基于 coco 协程库实现高并发静态资源服务器。
  * 每个客户端连接由一个独立的协程处理，主线程负责 accept。
@@ -23,6 +20,7 @@
 #include "static.h"
 #include "cocoon.h"
 #include "log.h"
+#include "multipart.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -191,17 +189,91 @@ static int conn_read_body(connection_t *conn, http_request_t *req, size_t need)
 /**
  * handle_post_request - 处理 POST 请求
  *
- * 目前仅提供 JSON 回显和表单回显，用于测试和 API 场景。
- * 支持 application/json 和 application/x-www-form-urlencoded。
+ * 支持 multipart/form-data 文件上传、JSON 回显和表单回显。
  *
  * @param fd 客户端 socket
  * @param req HTTP 请求
+ * @param root_dir 静态资源根目录（用于保存上传文件）
  * @return true 保持连接
  */
-static bool handle_post_request(int fd, const http_request_t *req) {
+static bool handle_post_request(int fd, const http_request_t *req, const char *root_dir) {
     char response[4096];
     int n = 0;
 
+    /* multipart/form-data 文件上传 */
+    if (strstr(req->content_type, "multipart/form-data") != NULL) {
+        char boundary[256];
+        if (!multipart_extract_boundary(req->content_type, boundary, sizeof(boundary))) {
+            static_send_error(fd, 400, req->keep_alive);
+            return req->keep_alive;
+        }
+
+        multipart_part_t *parts = NULL;
+        int num_parts = 0;
+        if (multipart_parse(req->body, req->body_len, boundary, &parts, &num_parts) != 0) {
+            static_send_error(fd, 400, req->keep_alive);
+            return req->keep_alive;
+        }
+
+        /* 构建 JSON 响应 */
+        n += snprintf(response + n, sizeof(response) - n,
+            "{\"method\":\"%s\",\"path\":\"%s\",\"uploaded\":%d,\"files\":[",
+            http_method_str(req->method), req->path, num_parts);
+
+        int files_saved = 0;
+        for (int i = 0; i < num_parts; i++) {
+            if (parts[i].filename && parts[i].filename[0] && parts[i].data_len > 0) {
+                /* 保存文件到 root_dir/uploads/ */
+                char upload_dir[4096];
+                int r = snprintf(upload_dir, sizeof(upload_dir), "%s/uploads", root_dir);
+                if (r > 0 && r < (int)sizeof(upload_dir)) {
+                    /* 创建目录（忽略已存在错误） */
+                    mkdir(upload_dir, 0755);
+
+                    char file_path[4096];
+                    r = snprintf(file_path, sizeof(file_path), "%s/%s", upload_dir, parts[i].filename);
+                    if (r > 0 && r < (int)sizeof(file_path)) {
+                        FILE *fp = fopen(file_path, "wb");
+                        if (fp) {
+                            fwrite(parts[i].data, 1, parts[i].data_len, fp);
+                            fclose(fp);
+                            files_saved++;
+
+                            if (files_saved > 1) {
+                                n += snprintf(response + n, sizeof(response) - n, ",");
+                            }
+                            n += snprintf(response + n, sizeof(response) - n,
+                                "{\"field\":\"%s\",\"filename\":\"%s\",\"size\":%zu,\"path\":\"%s\"}",
+                                parts[i].name ? parts[i].name : "",
+                                parts[i].filename,
+                                parts[i].data_len,
+                                file_path);
+                        }
+                    }
+                }
+            }
+        }
+
+        n += snprintf(response + n, sizeof(response) - n, "]}");
+
+        multipart_parts_free(parts, num_parts);
+
+        char header[512];
+        int header_len = snprintf(header, sizeof(header),
+            "HTTP/1.1 200 OK\r\n"
+            "Content-Type: application/json\r\n"
+            "Content-Length: %d\r\n"
+            "Connection: %s\r\n"
+            "Server: Cocoon/1.0\r\n"
+            "\r\n",
+            n, req->keep_alive ? "keep-alive" : "close");
+
+        send_all(fd, header, (size_t)header_len);
+        send_all(fd, response, (size_t)n);
+
+        return req->keep_alive;
+    }
+
     n += snprintf(response + n, sizeof(response) - n,
         "{\"method\":\"%s\",\"path\":\"%s\",\"content_type\":\"%s\",\"body_length\":%zu",
         http_method_str(req->method), req->path, req->content_type, req->body_len);
@@ -291,7 +363,7 @@ static bool handle_request(connection_t *conn, const char *root_dir) {
 
     /* 处理 POST */
     if (req.method == HTTP_POST) {
-        bool keep = handle_post_request(conn->fd, &req);
+        bool keep = handle_post_request(conn->fd, &req, conn->root_dir);
         http_request_free(&req);
         return keep;
     }
diff --git a/static.c b/static.c
index c569b4e..870f0b4 100644
--- a/static.c
+++ b/static.c
@@ -1,4 +1,3 @@
-#define _GNU_SOURCE
 
 /**
  * static.c - 静态资源服务实现