diff --git a/src/rootPages/Designer/properties/dataFields/ABFieldLongText.js b/src/rootPages/Designer/properties/dataFields/ABFieldLongText.js
index bfa0f4f..268cbb7 100644
--- a/src/rootPages/Designer/properties/dataFields/ABFieldLongText.js
+++ b/src/rootPages/Designer/properties/dataFields/ABFieldLongText.js
@@ -16,6 +16,7 @@ export default function (AB) {
          super(`${ibase}_longtext`, {
             default: "",
             defaultCheckbox: "",
+            maxLength: "",  // <-- 新增 ID
          });
       }
 
@@ -61,6 +62,32 @@ export default function (AB) {
                   },
                ],
             },
+            {
+               view: "layout",
+               cols: [
+                  {
+                     view: "label",
+                     label: L("Max Length:"),
+                     align: "right",
+                     width: 100,
+                  },
+                  {
+                     id: ids.maxLength,
+                     view: "counter",
+                     name: "maxLength",
+                     min: 1,
+                     max: 10000,
+                     step: 1,
+                     labelWidth: uiConfig.labelWidthXLarge,
+                     placeholder: L("Optional limit"),
+                     on: {
+                        onAfterRender: function () {
+                           ABField.CYPRESS_REF(this);
+                        },
+                     },
+                  },
+               ],
+            },
             {
                view: "checkbox",
                name: "supportMultilingual",
@@ -89,13 +116,25 @@ export default function (AB) {
 
       populate(field) {
          super.populate(field);
+
          const value = field.settings.default === "" ? 0 : 1;
          $$(this.ids.defaultCheckbox).setValue(value);
+         $$(this.ids.default).setValue(field.settings.default || "");
+
+         // 新增：设置 maxLength 值
+         if (field.settings.maxLength) {
+            $$(this.ids.maxLength).setValue(field.settings.maxLength);
+         }
       }
 
       show() {
          super.show();
          $$(this.ids.defaultCheckbox).setValue(0);
+         $$(this.ids.default).setValue("");
+         $$(this.ids.default).disable();
+
+         // 新增：清空 maxLength
+         $$(this.ids.maxLength).setValue("");
       }
 
       checkboxDefaultValue(state) {
@@ -106,6 +145,19 @@ export default function (AB) {
             $$(this.ids.default).enable();
          }
       }
+
+      values() {
+         const values = super.values();
+
+         values.default = $$(this.ids.defaultCheckbox).getValue()
+            ? $$(this.ids.default).getValue()
+            : "";
+
+         // 加入 maxLength 保存
+         values.maxLength = parseInt($$(this.ids.maxLength).getValue()) || null;
+
+         return values;
+      }
    }
 
    return ABFieldLongText;