diff --git a/include/log.h b/include/log.h
new file mode 100644
index 0000000..1108984
--- /dev/null
+++ b/include/log.h
@@ -0,0 +1,25 @@
+#ifndef _LOG_H
+#define _LOG_H
+
+#include <time.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+enum {
+    LOG_DEBUG,
+    LOG_INFO,
+    LOG_WARN,
+    LOG_ERROR,
+    LOG_FATAL
+};
+
+#define log_debug(...) log_printf(LOG_DEBUG, __VA_ARGS__)
+#define log_info(...) log_printf(LOG_INFO,  __VA_ARGS__)
+#define log_warn(...) log_printf(LOG_WARN,  __VA_ARGS__)
+#define log_error(...) log_printf(LOG_ERROR, __VA_ARGS__)
+#define log_fatal(...) log_printf(LOG_FATAL, __VA_ARGS__)
+
+extern int log_level;
+void log_printf(int level, const char *fmt, ...);
+
+#endif
diff --git a/src/local.c b/src/local.c
index cbe9e66..b8675fe 100644
--- a/src/local.c
+++ b/src/local.c
@@ -3,6 +3,7 @@
 #include <string.h>
 #include "common.h"
 #include "process.h"
+#include "log.h"
 
 #define SHADOWSOCKS_DEFAULT "sslocal"
 
@@ -38,16 +39,23 @@ void show_help() { // show help message
 
 int main(int argc, char *argv[]) {
     int i;
-    if (argc <= 1) {
-        show_help();
-    }
-    for (i = 0; i < argc; ++i) {
-        if (!strcmp(argv[i], "-h") || !strcmp(argv[i], "--help")) {
-            show_help();
-        }
-    }
-    args_decode(argc, argv);
-    params_load(SHADOWSOCKS_DEFAULT); // default file name
-    start_bootstrap(SHADOWSOCKS_DEFAULT, is_udp_proxy); // local or server mode
+
+    log_debug("%s", "shadowsocks-bootstrap log level debug");
+    log_info("%s", "shadowsocks-bootstrap log level info");
+    log_warn("%s", "shadowsocks-bootstrap log level warn");
+    log_error("%s", "shadowsocks-bootstrap log level error");
+    log_fatal("%s", "shadowsocks-bootstrap log level fatal");
+
+//    if (argc <= 1) {
+//        show_help();
+//    }
+//    for (i = 0; i < argc; ++i) {
+//        if (!strcmp(argv[i], "-h") || !strcmp(argv[i], "--help")) {
+//            show_help();
+//        }
+//    }
+//    args_decode(argc, argv);
+//    params_load(SHADOWSOCKS_DEFAULT); // default file name
+//    start_bootstrap(SHADOWSOCKS_DEFAULT, is_udp_proxy); // local or server mode
     return 0;
 }
diff --git a/src/log.c b/src/log.c
new file mode 100644
index 0000000..c363435
--- /dev/null
+++ b/src/log.c
@@ -0,0 +1,37 @@
+#include "log.h"
+
+int log_level = LOG_DEBUG; // default log level
+
+static const char *log_string[] = {
+    "[DEBUG]",
+    "[INFO]",
+    "[WARN]",
+    "[ERROR]",
+    "[FATAL]",
+};
+
+static const char *log_color[] = {
+    "\x1b[39m", // debug
+    "\x1b[32m", // info
+    "\x1b[33m", // warn
+    "\x1b[31m", // error
+    "\x1b[95m", // fatal
+};
+
+void log_printf(int level, const char *fmt, ...) {
+    if (level < log_level) { // skip low log level
+        return;
+    }
+    time_t t = time(NULL);
+    char time_str[20]; // YYYY-mm-dd HH:MM:SS (20 bytes)
+    time_str[strftime(time_str, 20, "%Y-%m-%d %H:%M:%S", localtime(&t))] = '\0'; // generate time str
+
+    va_list ap;
+    va_start(ap, fmt);
+    fprintf(stderr, "\x1b[36m[Bootstrap]\x1b[0m \x1b[90m%s\x1b[0m", time_str); // show log prefix
+    fprintf(stderr, " %s%s\x1b[0m ", log_color[level], log_string[level]); // show log level
+    vfprintf(stderr, fmt, ap); // output log content
+    fprintf(stderr, "\n"); // add LF after line
+    fflush(stderr);
+    va_end(ap);
+}