diff --git a/src/syntax/def.lalrpop b/src/syntax/def.lalrpop
index bbc6809..4a82e3f 100644
--- a/src/syntax/def.lalrpop
+++ b/src/syntax/def.lalrpop
@@ -785,7 +785,6 @@ pub Control: LogicLine = {
             )
             .max()
             .unwrap();
-        let mut cases_res = Vec::with_capacity(case_num_max + 1);
 
         // 用于填充填充case的行, 如果有追加在末尾的行则将其封装并替换填充
         let mut fill_line = append
@@ -841,6 +840,9 @@ pub Control: LogicLine = {
             catch_lines.push(Expand(out_block).into())
         }
 
+        let mut cases_res = Vec::with_capacity(case_num_max + 1);
+        let mut cases_res_isline = vec![false; case_num_max + 1];
+
         let mut next_ignored_num = 0;
         for (mut nums, mut expand) in cases {
             if let Some(append) = &append {
@@ -849,12 +851,22 @@ pub Control: LogicLine = {
             if nums.is_empty() { nums.push(next_ignored_num) }
             for num in nums {
                 for _ in cases_res.len()..=num {
-                    cases_res.push(fill_line.clone())
+                    cases_res.push(LogicLine::Ignore);
                 }
                 cases_res[num] = expand.clone().into();
+                cases_res_isline[num] = true;
                 next_ignored_num = num + 1;
             }
         }
+        // 将填充行填入填充case
+        let mut iter = cases_res_isline.into_iter().enumerate().peekable();
+        while let Some((idx, is_line)) = iter.next() {
+            if is_line { continue }
+            match iter.peek() {
+                Some((_, true)) => cases_res[idx] = fill_line.clone(),
+                _ => (),
+            }
+        }
         debug_assert_eq!(cases_res.len(), case_num_max + 1);
         debug_assert_eq!(cases_res.len(), cases_res.capacity());
 
diff --git a/src/syntax/tests.rs b/src/syntax/tests.rs
index e9ed7ac..1aa4a7d 100644
--- a/src/syntax/tests.rs
+++ b/src/syntax/tests.rs
@@ -3686,3 +3686,33 @@ fn switch_ignored_id_test() {
         "#).unwrap(),
     );
 }
+
+#[test]
+fn switch_append_tail_once_test() {
+    let parser = TopLevelParser::new();
+
+    // switch填充行仅最后一个进行填充
+
+    assert_eq!(
+        parse!(parser, r#"
+        switch x {
+            break;
+            case 6:
+                foo;
+            case 3:
+                bar;
+        }
+        "#).unwrap(),
+        parse!(parser, r#"
+        select x {
+            print; # ignore
+            print;
+            { break; } # switch的封装以限制作用域
+            { bar; break; }
+            print;
+            { break; }
+            { foo; break; }
+        }
+        "#).unwrap(),
+    );
+}