diff --git a/src/main.cpp b/src/main.cpp
index cc0d5e3..78d0d72 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -7,11 +7,16 @@
 #include "irgen/IRGen.h"
 #include "sem/Sema.h"
 #include "utils/CLI.h"
+#include "utils/Log.h"
 #include "ast/AstNodes.h"
 
 int main(int argc, char** argv) {
   try {
     auto opts = ParseCLI(argc, argv);
+    if (opts.show_help) {
+      PrintHelp(std::cout);
+      return 0;
+    }
     auto antlr = ParseFileWithAntlr(opts.input);
     auto ast = BuildAst(antlr.tree);
     ast::PrintAST(*ast);  // 调试 AST
diff --git a/src/utils/CLI.cpp b/src/utils/CLI.cpp
index d9882db..f8120bc 100644
--- a/src/utils/CLI.cpp
+++ b/src/utils/CLI.cpp
@@ -5,13 +5,38 @@
 
 #include "utils/CLI.h"
 
+#include <cstring>
+#include <string>
 #include <stdexcept>
 
 CLIOptions ParseCLI(int argc, char** argv) {
+  CLIOptions opt;
+
   if (argc <= 1) {
-    throw std::runtime_error("用法: compiler <input.sy>");
+    throw std::runtime_error("用法: compiler [--help] <input.sy>");
+  }
+
+  for (int i = 1; i < argc; ++i) {
+    const char* arg = argv[i];
+    if (std::strcmp(arg, "-h") == 0 || std::strcmp(arg, "--help") == 0) {
+      opt.show_help = true;
+      return opt;
+    }
+
+    if (arg[0] == '-') {
+      throw std::runtime_error(std::string("未知参数: ") + arg +
+                               "（使用 --help 查看用法）");
+    }
+
+    if (!opt.input.empty()) {
+      throw std::runtime_error(
+          "参数过多：当前只支持 1 个输入文件（使用 --help 查看用法）");
+    }
+    opt.input = arg;
+  }
+
+  if (opt.input.empty()) {
+    throw std::runtime_error("缺少输入文件：请提供 <input.sy>（使用 --help 查看用法）");
   }
-  CLIOptions opt;
-  opt.input = argv[1];
   return opt;
 }
diff --git a/src/utils/CLI.h b/src/utils/CLI.h
index f69c583..618b9e1 100644
--- a/src/utils/CLI.h
+++ b/src/utils/CLI.h
@@ -5,6 +5,7 @@
 
 struct CLIOptions {
   std::string input;
+  bool show_help = false;
 };
 
 CLIOptions ParseCLI(int argc, char** argv);
diff --git a/src/utils/Log.cpp b/src/utils/Log.cpp
index af90bdc..e1702a3 100644
--- a/src/utils/Log.cpp
+++ b/src/utils/Log.cpp
@@ -3,3 +3,19 @@
 // - 提供可配置的日志级别与输出位置（按需要实现）
 
 #include "utils/Log.h"
+
+#include <ostream>
+
+void PrintHelp(std::ostream& os) {
+  os << "SysY Compiler (课程实验最小可运行示例)\n"
+     << "\n"
+     << "用法:\n"
+     << "  compiler [--help] <input.sy>\n"
+     << "\n"
+     << "选项:\n"
+     << "  -h, --help        打印帮助信息并退出\n"
+     << "\n"
+     << "说明:\n"
+     << "  - 当前默认将 IR 输出到标准输出，可使用重定向写入文件:\n"
+     << "      compiler test/test_case/simple_add.sy > out.ll\n";
+}
diff --git a/src/utils/Log.h b/src/utils/Log.h
index 09d31a7..ac15b2c 100644
--- a/src/utils/Log.h
+++ b/src/utils/Log.h
@@ -1,7 +1,11 @@
 // 轻量日志接口。
 #pragma once
 
+#include <iosfwd>
 #include <iostream>
 
 #define LOG_INFO(msg) std::cerr << "[info] " << msg << "\n"
 #define LOG_ERROR(msg) std::cerr << "[error] " << msg << "\n"
+
+// 打印命令行帮助信息（用于 `compiler --help`）。
+void PrintHelp(std::ostream& os);