diff --git a/CMakeLists.txt b/CMakeLists.txt
index e8b4552..0147d1c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,13 +1,13 @@
 project(simple-kanban)
-add_executable(simple-kanban server.c) # 生成可执行文件
-add_executable(simple-kanban-client client.c) # 生成可执行文件
-target_link_libraries(  # 目标库
-                        simple-kanban
- 
-                        # 目标库需要链接的库
-                        pthread)
-target_link_libraries(  # 目标库
-                        simple-kanban-client
- 
-                        # 目标库需要链接的库
-                        pthread)
+
+include(TestBigEndian)
+test_big_endian(isBigEndian)
+if (${isBigEndian})
+    set ( WORDS_BIGENDIAN 1 )
+endif()
+
+add_executable(simple-kanban server.c)
+add_executable(simple-kanban-client client.c)
+
+target_link_libraries(simple-kanban pthread)
+target_link_libraries(simple-kanban-client pthread)
diff --git a/README.md b/README.md
index 5613b17..607eff6 100644
--- a/README.md
+++ b/README.md
@@ -72,10 +72,10 @@ make
 ## 0. 启动程序
 
 ```bash
-./simple-kanban-client 127.0.0.1 7777 [-b]
+./simple-kanban-client 127.0.0.1 7777 [-r]
 ```
 
-接下来即可按照上面的交互流程开始使用。其中末尾的`-b`为可选项（程序只判断参数个数所以请务必放到末尾），表示以大端序发送文件长度。
+接下来即可按照上面的交互流程开始使用。其中末尾的`-r`为可选项（程序只判断参数个数所以请务必放到末尾），表示以与本机相反的顺序发送文件长度。
 
 ## 1. 发送命令
 
diff --git a/client.c b/client.c
index 37f2382..4198540 100644
--- a/client.c
+++ b/client.c
@@ -43,7 +43,7 @@ off_t size_of_file(const char* fname) {
     else return -1;
 }
 
-int main(int argc,char *argv[]) {   //usage: ./client host port [-d]
+int main(int argc,char *argv[]) {   //usage: ./client host port [-r]
     ssize_t numbytes;
     puts("break!");
     while((sockfd = socket(AF_INET,SOCK_STREAM,0)) == -1);
@@ -74,8 +74,8 @@ int main(int argc,char *argv[]) {   //usage: ./client host port [-d]
                 if(fp) {
                     off_t len = 0;
                     file_size = (uint32_t)size_of_file(buf);
-                    if(argc == 4) file_size = htonl(file_size);
                     #if __APPLE__
+                        if(argc == 4) file_size = htonl(file_size);
                         struct iovec headers;
                         headers.iov_base = &file_size;
                         headers.iov_len = sizeof(uint32_t);
@@ -86,7 +86,10 @@ int main(int argc,char *argv[]) {   //usage: ./client host port [-d]
                         if(!sendfile(fileno(fp), sockfd, 0, &len, &hdtr, 0)) puts("Send file success.");
                         else puts("Send file error.");
                     #else
-                        send(sockfd, &file_size, sizeof(uint32_t), 0);
+                        if(argc == 4) {
+                            uint32_t fs = htonl(file_size);
+                            send(sockfd, &fs, sizeof(uint32_t), 0);
+                        } else send(sockfd, &file_size, sizeof(uint32_t), 0);
                         if(!sendfile(sockfd, fileno(fp), &len, file_size)) puts("Send file success.");
                         else puts("Send file error.");
                     #endif
diff --git a/server.c b/server.c
index 027870e..4ea157c 100644
--- a/server.c
+++ b/server.c
@@ -121,6 +121,7 @@ int send_all(char* file_path, THREADTIMER *timer) {
         printf("Get file size: %u bytes.\n", file_size);
         off_t len = 0;
         #if __APPLE__
+            //苹果基本没有大端，不作处理
             struct sf_hdtr hdtr;
             struct iovec headers;
             headers.iov_base = &file_size;
@@ -132,7 +133,12 @@ int send_all(char* file_path, THREADTIMER *timer) {
             re = !sendfile(fileno(fp), timer->accept_fd, 0, &len, &hdtr, 0);
             if(!re) perror("Sendfile");
         #else
-            send(timer->accept_fd, &file_size, sizeof(uint32_t), 0);
+            #if WORDS_BIGENDIAN
+                uint32_t little_fs = htonl(file_size);
+                send(timer->accept_fd, &little_fs sizeof(uint32_t), 0);
+            #else
+                send(timer->accept_fd, &file_size, sizeof(uint32_t), 0);
+            #endif
             re = sendfile(timer->accept_fd, fileno(fp), &len, file_size) >= 0;
             if(!re) perror("Sendfile");
         #endif