diff --git a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/TodoEditorPage.kt b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/TodoEditorPage.kt
index c77b033..eb2db7f 100644
--- a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/TodoEditorPage.kt
+++ b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/TodoEditorPage.kt
@@ -205,6 +205,15 @@ fun TodoEditorPage(
                         value = uiState.categoryContent,
                         onValueChange = { uiState.categoryContent = it },
                         isError = uiState.isErrorCategory,
+                        supportingText = when {
+                            uiState.categoryContent.trim().isEmpty() ->
+                                stringResource(R.string.error_no_content_entered)
+
+                            uiState.categoryContent.length > 5 ->
+                                stringResource(R.string.error_exceeds_5_chars)
+
+                            else -> stringResource(R.string.tip_max_length_5)
+                        },
                         modifier = Modifier
                             .fillMaxWidth()
                         /*.sharedBounds(
diff --git a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoEditorTextFields.kt b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoEditorTextFields.kt
index fa4e520..457a096 100644
--- a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoEditorTextFields.kt
+++ b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoEditorTextFields.kt
@@ -42,6 +42,7 @@ fun TodoCategoryTextField(
     value: String,
     onValueChange: (String) -> Unit,
     isError: Boolean,
+    supportingText: String = stringResource(R.string.tip_max_length_5),
     modifier: Modifier = Modifier
 ) {
     TextField(
@@ -49,15 +50,8 @@ fun TodoCategoryTextField(
         onValueChange = onValueChange,
         label = { Text(stringResource(R.string.label_enter_category_name)) },
         isError = isError,
-        supportingText = {
-            AnimatedVisibility(
-                visible = isError,
-                enter = fadeIn() + expandVertically(),
-                exit = fadeOut() + shrinkVertically()
-            ) {
-                Text(stringResource(R.string.error_no_content_entered))
-            }
-        },
+        supportingText = { Text(supportingText) },
+        maxLines = 1,
         modifier = modifier
     )
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/state/EditorState.kt b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/state/EditorState.kt
index c8c54a5..308a988 100644
--- a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/state/EditorState.kt
+++ b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/state/EditorState.kt
@@ -29,7 +29,9 @@ class EditorState(val initialTodo: TodoEntity? = null) {
      */
     fun setErrorIfNotValid(): Boolean {
         isErrorContent = toDoContent.trim().isEmpty()
-        isErrorCategory = if (selectedCategoryIndex == -1) categoryContent.trim().isEmpty() else false
+        isErrorCategory = if (selectedCategoryIndex == -1) {
+            categoryContent.trim().isEmpty() || categoryContent.trim().length > 5
+        } else false
         return isErrorContent || isErrorCategory
     }