diff --git a/desktop/src-tauri/src/main.rs b/desktop/src-tauri/src/main.rs
index f249ebec..35aeb8d6 100644
--- a/desktop/src-tauri/src/main.rs
+++ b/desktop/src-tauri/src/main.rs
@@ -1,13 +1,31 @@
 // Prevents additional console window on Windows in release
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
 
+use std::fs;
+use std::path::PathBuf;
+
 fn main() {
-    // If CLAUDE_CONFIG_DIR is set (e.g. via portable launcher), also redirect
-    // WebView2 user data folder so EBWebView cache lives alongside it instead of
-    // under %LOCALAPPDATA%\com.claude-code-haha.desktop\.
+    // Determine if we should start in portable mode and set CLAUDE_CONFIG_DIR
+    // before any Tauri/WebView2 initialization.
+    //
+    // Mode resolution order:
+    //   1. External CLAUDE_CONFIG_DIR env var (batch script etc.) — always respected
+    //   2. Persisted app-mode.json saying "portable"
+    //   3. Auto-detect: default portable dir already has data files
+    //
+    // In "default" mode the app does NOT set CLAUDE_CONFIG_DIR itself.
+    // It relies on the env var (if set externally) or falls back to system dirs.
+    // All existing std::env::var("CLAUDE_CONFIG_DIR") checks in lib.rs handle this.
+
+    if let Some(portable_dir) = determine_startup_portable_dir() {
+        std::env::set_var("CLAUDE_CONFIG_DIR", portable_dir.to_string_lossy().to_string());
+    }
+
+    // If CLAUDE_CONFIG_DIR is set (either from env or from our startup logic above),
+    // redirect WebView2 user data folder so EBWebView cache lives alongside it.
     if let Ok(config_dir) = std::env::var("CLAUDE_CONFIG_DIR") {
-        let webview_data = std::path::PathBuf::from(&config_dir).join("EBWebView");
-        if let Err(e) = std::fs::create_dir_all(&webview_data) {
+        let webview_data = PathBuf::from(&config_dir).join("EBWebView");
+        if let Err(e) = fs::create_dir_all(&webview_data) {
             eprintln!("[desktop] failed to create EBWebView dir: {e}");
         }
         std::env::set_var("WEBVIEW2_USER_DATA_FOLDER", &webview_data);
@@ -15,3 +33,76 @@ fn main() {
 
     claude_code_desktop_lib::run()
 }
+
+/// Determine if we should start in portable mode.
+/// Returns the portable config directory path if yes, None for default mode.
+fn determine_startup_portable_dir() -> Option<PathBuf> {
+    // 1. 如果外部已经设置了 CLAUDE_CONFIG_DIR 环境变量，我们不应该覆盖它，直接返回 None 让 main 保持原样
+    if std::env::var("CLAUDE_CONFIG_DIR").is_ok() {
+        return None;
+    }
+
+    let exe = std::env::current_exe().ok()?;
+    let exe_dir = exe.parent()?;
+    let mut default_portable = exe_dir.to_path_buf();
+    default_portable.push("CLAUDE_CONFIG_DIR");
+
+    // 辅助函数：读取 app-mode.json 获取模式和自定义便携路径
+    fn get_mode_from_config(dir: &std::path::Path) -> Option<(String, Option<PathBuf>)> {
+        let path = dir.join("app-mode.json");
+        let data = std::fs::read_to_string(&path).ok()?;
+        let parsed: serde_json::Value = serde_json::from_str(&data).ok()?;
+        let mode = parsed.get("mode").and_then(|m| m.as_str()).unwrap_or("default").to_string();
+        let portable_dir = parsed.get("portable_dir").and_then(|v| v.as_str()).map(PathBuf::from);
+        Some((mode, portable_dir))
+    }
+
+    // 2. 优先检查便携目录本地的配置文件（保证移动便携版到新电脑依然生效，并能正确处理切回默认模式）
+    if let Some((mode, portable_dir)) = get_mode_from_config(&default_portable) {
+        if mode == "portable" {
+            return Some(portable_dir.unwrap_or(default_portable.clone()));
+        } else {
+            return None; // 明确设置了 default，直接使用系统默认
+        }
+    }
+
+    // 3. 检查系统全局配置
+    #[cfg(target_os = "windows")]
+    let system_config: Option<PathBuf> = std::env::var("APPDATA").ok().map(PathBuf::from);
+    #[cfg(target_os = "macos")]
+    let system_config: Option<PathBuf> = std::env::var("HOME").ok().map(|h| PathBuf::from(h).join("Library").join("Application Support"));
+    #[cfg(target_os = "linux")]
+    let system_config: Option<PathBuf> = std::env::var("XDG_CONFIG_HOME")
+        .ok().map(PathBuf::from)
+        .or_else(|| std::env::var("HOME").ok().map(|h| PathBuf::from(h).join(".config")));
+
+    if let Some(ref sys_cfg) = system_config {
+        // 修复：必须使用 Tauri 默认的 bundle identifier
+        let app_subdir = sys_cfg.join("com.claude-code-haha.desktop");
+        if let Some((mode, portable_dir)) = get_mode_from_config(&app_subdir) {
+            if mode == "portable" {
+                return Some(portable_dir.unwrap_or(default_portable.clone()));
+            } else {
+                return None; // 明确设置了 default
+            }
+        }
+    }
+
+    // 4. 自动检测：如果默认便携目录中已经存在数据文件，则自动进入便携模式
+    fn dir_has_portable_data(dir: &std::path::Path) -> bool {
+        if !dir.is_dir() {
+            return false;
+        }
+        ["window-state.json", "terminal-config.json"]
+            .iter()
+            .any(|f| dir.join(f).is_file())
+            || dir.join("Cache").is_dir()
+            || dir.join("EBWebView").is_dir()
+    }
+
+    if dir_has_portable_data(&default_portable) {
+        return Some(default_portable);
+    }
+
+    None
+}