diff --git a/internal/bot/bot.go b/internal/bot/bot.go
index 867efce..c929176 100644
--- a/internal/bot/bot.go
+++ b/internal/bot/bot.go
@@ -139,9 +139,12 @@ func (b *Bot) Tools() []string {
 	return b.toolRegistry.List()
 }
 
-// ClearHistory 清空内存中的会话历史，开启新对话（系统提示词保留）。
+// ClearHistory 清空内存中的会话历史，开启新对话；系统提示词重置为配置加载的文件内容。
 func (b *Bot) ClearHistory() {
 	b.history = nil
+	if b.cfg != nil {
+		b.systemPrompt = b.cfg.SystemPrompt
+	}
 }
 
 func (b *Bot) ContextWindow() int64 {
diff --git a/internal/bot/session_test.go b/internal/bot/session_test.go
index a13f332..3b78611 100644
--- a/internal/bot/session_test.go
+++ b/internal/bot/session_test.go
@@ -89,11 +89,12 @@ func TestRestoreTrimsHistory(t *testing.T) {
 func TestClearHistory(t *testing.T) {
 	b := newTestBot(t)
 	b.history = append(b.history, openai.UserMessage("hi"))
+	b.systemPrompt = "被会话覆盖的旧提示词"
 	b.ClearHistory()
 	if len(b.history) != 0 {
 		t.Errorf("history 应清空, got %d", len(b.history))
 	}
 	if b.systemPrompt != "测试系统提示" {
-		t.Errorf("systemPrompt 应保留: %q", b.systemPrompt)
+		t.Errorf("systemPrompt 应重置为配置内容, got %q", b.systemPrompt)
 	}
 }