diff --git a/include/common.h b/include/common.h
index 6e6b71c..870ba1a 100644
--- a/include/common.h
+++ b/include/common.h
@@ -23,5 +23,6 @@
 
 char* show_bool(int value);
 char** command_init(char *bin);
+void save_file(char *file, char *data);
 
 #endif
diff --git a/include/dnsproxy.h b/include/dnsproxy.h
index b193d22..076e00d 100644
--- a/include/dnsproxy.h
+++ b/include/dnsproxy.h
@@ -19,6 +19,6 @@ void dnsproxy_add_primary(dnsproxy *info, char *server);
 void dnsproxy_add_fallback(dnsproxy *info, char *server);
 void dnsproxy_add_bootstrap(dnsproxy *info, char *server);
 
-void dnsproxy_gen_config(dnsproxy *info);
+char* dnsproxy_gen_config(dnsproxy *info);
 
 #endif
diff --git a/src/cleardns.c b/src/cleardns.c
index b8c5dfc..ad96ea0 100644
--- a/src/cleardns.c
+++ b/src/cleardns.c
@@ -52,7 +52,10 @@ int main(int argc, char *argv[]) { // ClearDNS server
 
     dnsproxy_dump("Domestic", domestic);
 
-    dnsproxy_gen_config(domestic);
+    char *config = dnsproxy_gen_config(domestic);
+    log_info("\n%s", config);
+
+    save_file("/tmp/test.txt", config);
 
 //    int debug_mode = 0;
 //    fprintf(stderr, "[ClearDNS] Server start.\n");
diff --git a/src/common.c b/src/common.c
index e09e394..543529a 100644
--- a/src/common.c
+++ b/src/common.c
@@ -1,4 +1,6 @@
+#include <stdio.h>
 #include "common.h"
+#include "logger.h"
 #include "strList.h"
 
 char* show_bool(int value) {
@@ -12,3 +14,14 @@ char* show_bool(int value) {
 char** command_init(char *bin) {
     return string_list_append(string_list_init(), bin);
 }
+
+void save_file(char *file, char *content) {
+    log_debug("Write into `%s` -> \n%s", file, content);
+    FILE* fp = fopen(file , "w");
+    if (fp == NULL) {
+        log_fatal("Fail to open file -> %s", file);
+    }
+    fputs(content, fp);
+    fclose(fp);
+    log_debug("Save `%s` success", file);
+}
diff --git a/src/dnsproxy.c b/src/dnsproxy.c
index 9d39ec7..534a5a4 100644
--- a/src/dnsproxy.c
+++ b/src/dnsproxy.c
@@ -1,10 +1,8 @@
 #include <stdlib.h>
-#include <string.h>
 #include "dnsproxy.h"
+#include "strList.h"
 #include "logger.h"
 #include "common.h"
-#include "strList.h"
-
 #include "cJSON.h"
 
 dnsproxy* dnsproxy_init(int port) {
@@ -43,7 +41,7 @@ void dnsproxy_add_bootstrap(dnsproxy *info, char *server) {
     info->bootstrap = string_list_append(info->bootstrap, server);
 }
 
-void dnsproxy_gen_config(dnsproxy *info) {
+char* dnsproxy_gen_config(dnsproxy *info) {
     cJSON *config = cJSON_CreateObject();
     if (!info->verify) {
         cJSON_AddTrueToObject(config, "insecure"); // insecure --(default)--> `false`
@@ -81,5 +79,7 @@ void dnsproxy_gen_config(dnsproxy *info) {
     }
     cJSON_AddItemToObject(config, "upstream", primary);
 
-    log_info("\n%s", cJSON_Print(config));
+    char *config_str = cJSON_Print(config);
+    cJSON_Delete(config);
+    return config_str;
 }