diff --git a/components/panel/formSlot.vue b/components/panel/formSlot.vue
index bd9ea82..587d417 100644
--- a/components/panel/formSlot.vue
+++ b/components/panel/formSlot.vue
@@ -889,9 +889,7 @@ export default {
 					// 已展开，则收起该节点及其后续展开
 					this.expandedDeptIds = this.expandedDeptIds.slice(0, colIndex);
 					// 清除后续列的 padding-top
-					for (let i = colIndex + 1; i <= Object.keys(this.columnPaddingTops).length; i++) {
-						this.$delete(this.columnPaddingTops, i);
-					}
+					this.clearColumnPaddingTops(colIndex);
 				} else {
 					// 未展开或展开了其他节点，则设置当前节点为展开，并截断后续
 					this.expandedDeptIds = this.expandedDeptIds.slice(0, colIndex);
@@ -904,6 +902,16 @@ export default {
 				});
 			}
 		},
+		// 清除指定列之后所有列的 padding-top
+		clearColumnPaddingTops(colIndex) {
+			let newPaddingTops = {};
+			Object.keys(this.columnPaddingTops).forEach(key => {
+				if (Number(key) <= colIndex) {
+					newPaddingTops[key] = this.columnPaddingTops[key];
+				}
+			});
+			this.columnPaddingTops = newPaddingTops;
+		},
 		// 滚动子级列，使其顶部与父级节点垂直对齐
 		alignColumnToParent(colIndex, deptIndex) {
 			let that = this;
@@ -918,7 +926,9 @@ export default {
 					let offset = parentRect.top - firstRect.top;
 					if (offset > 0) {
 						// 给子级列设置相同的 padding-top，使子级列第一项与父级节点垂直对齐
-						that.$set(that.columnPaddingTops, colIndex + 1, offset);
+						let newPaddingTops = Object.assign({}, that.columnPaddingTops);
+						newPaddingTops[colIndex + 1] = offset;
+						that.columnPaddingTops = newPaddingTops;
 					}
 				}).exec();
 			}).exec();