diff --git a/ch2/user/src/bin/00hello_world.rs b/ch2/user/src/bin/00hello_world.rs
index fbf31f5..965827b 100644
--- a/ch2/user/src/bin/00hello_world.rs
+++ b/ch2/user/src/bin/00hello_world.rs
@@ -1,9 +1,9 @@
 #![no_std]
 #![no_main]
 
-use user_lib;
+use user_lib::*;
 
 #[no_mangle]
 fn main() {
-
+    println!("123");
 }
\ No newline at end of file
diff --git a/ch2/user/src/lib.rs b/ch2/user/src/lib.rs
index 7c21dcb..081d219 100644
--- a/ch2/user/src/lib.rs
+++ b/ch2/user/src/lib.rs
@@ -2,7 +2,8 @@
 #![feature(linkage)]  // 开启弱链接特性
 #![feature(panic_info_message)]
 
-mod user_lang_items;
+pub mod user_lang_items;
+pub use user_lang_items::*;
 
 #[linkage = "weak"]  // 设置我们默认的main函数, 弱链接
 #[no_mangle]
diff --git a/ch2/user/src/user_lang_items.rs b/ch2/user/src/user_lang_items.rs
index 59f155e..fb50fe9 100644
--- a/ch2/user/src/user_lang_items.rs
+++ b/ch2/user/src/user_lang_items.rs
@@ -1 +1,2 @@
 pub mod user_panic;
+pub mod user_console;
\ No newline at end of file
diff --git a/ch2/user/src/user_lang_items/user_console.rs b/ch2/user/src/user_lang_items/user_console.rs
new file mode 100644
index 0000000..d1ca998
--- /dev/null
+++ b/ch2/user/src/user_lang_items/user_console.rs
@@ -0,0 +1,31 @@
+use core::fmt::{Arguments, Write, Result};
+
+struct Stdout;
+
+const STDOUT: usize = 1;
+
+impl Write for Stdout {
+    fn write_str(&mut self, s: &str) -> Result {
+        // ... todo 实现系统调用
+        Ok(())
+    }
+}
+
+pub fn print(args: Arguments) {
+    Stdout.write_fmt(args).unwrap();
+}
+
+
+#[macro_export]
+macro_rules! print {
+    ($fmt: literal $(, $($arg: tt)+)?) => {
+        $crate::user_console::print(format_args!($fmt $(, $($arg)+)?));
+    }
+}
+
+#[macro_export]
+macro_rules! println {
+    ($fmt: literal $(, $($arg: tt)+)?) => {
+        $crate::user_console::print(format_args!(concat!($fmt, "\n") $(, $($arg)+)?));
+    }
+}
\ No newline at end of file