diff --git a/packages/core/examples/features/lib/main.js b/packages/core/examples/features/lib/main.js
index a2f8f5d..05c8e95 100644
--- a/packages/core/examples/features/lib/main.js
+++ b/packages/core/examples/features/lib/main.js
@@ -46,6 +46,9 @@ core.on('changeScreen', (data) => {
 core.on('screenSelectElement', (data) => {
   console.log('screenSelectElement: ', data);
 });
+// core.on('screenHoverElement', (data) => {
+//   console.log('screenHoverElement: ', data);
+// });
 core.on('screenMoveElementStart', (data) => {
   console.log('screenMoveElementStart: ', data);
 });
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index b7baf32..f3936a4 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -14,9 +14,10 @@ import { CoreEvent, TypeCoreEventArgMap } from './lib/core-event';
 import { parseData } from './lib/parse';
 import is, { TypeIs } from './lib/is';
 import check, { TypeCheck } from './lib/check';
+import { TempData } from './lib/temp';
 import {
   _board, _data, _opts, _config, _renderer, _element, _helper, _hasInited,
-  _mode, _selectedUUID, _selectedUUIDList, _prevPoint, _draw,
+  _mode, _tempData, _prevPoint, _draw,
   _selectedDotDirection, _coreEvent, _mapper, _initEvent, _handlePoint,
   _handleMoveStart, _handleMove, _handleMoveEnd, _handleHover, _dragElements,
   _transfromElement, _emitChangeScreen, _emitChangeData, _onlyRender, _cursorStatus,
@@ -40,8 +41,7 @@ class Core {
   private [_hasInited] = false; 
   private [_mode]: Mode = Mode.NULL;
   private [_coreEvent]: CoreEvent = new CoreEvent();
-  private [_selectedUUID]: string | null = null;
-  private [_selectedUUIDList]: string[] = [];
+  private [_tempData]: TempData;
   private [_prevPoint]: TypePoint | null = null;
   private [_selectedDotDirection]: TypeHelperWrapperDotDirection | null = null;
   private [_onlyRender] = false;
@@ -55,7 +55,7 @@ class Core {
     this[_opts] = opts;
     this[_onlyRender] = opts.onlyRender === true;
     this[_config] = mergeConfig(config || {});
-
+    this[_tempData] = new TempData();
     this[_board] = new Board(mount, {
       ...this[_opts],
       canScroll: config?.scrollWrapper?.use,
@@ -82,8 +82,8 @@ class Core {
       width: this[_opts].width,
       height: this[_opts].height,
       canScroll: this[_config]?.scrollWrapper?.use === true,
-      selectedUUID: this[_selectedUUID],
-      selectedUUIDList: this[_selectedUUIDList],
+      selectedUUID: this[_tempData].get('selectedUUID'),
+      selectedUUIDList: this[_tempData].get('selectedUUIDList'),
       devicePixelRatio: this[_opts].devicePixelRatio,
       scale: transfrom.scale,
       scrollX: transfrom.scrollX,
@@ -108,8 +108,8 @@ class Core {
         this[_mode] = Mode.NULL;
       }
       if (typeof uuid === 'string') {
-        this[_selectedUUID] = uuid;
-        this[_selectedUUIDList] = [];
+        this[_tempData].set('selectedUUID', uuid);
+        this[_tempData].set('selectedUUIDList', []);
       }
       this[_draw]();
     }
@@ -243,17 +243,18 @@ class Core {
   }
 
   private [_initEvent](): void {
-    if (this[_onlyRender] === true) {
+    if (this[_hasInited] === true) {
       return;
     }
-    if (this[_hasInited] === true) {
+
+    this[_board].on('hover', time.throttle(this[_handleHover].bind(this), 32));
+    if (this[_onlyRender] === true) {
       return;
     }
     this[_board].on('point', this[_handlePoint].bind(this));
     this[_board].on('moveStart', this[_handleMoveStart].bind(this));
     this[_board].on('move', time.throttle(this[_handleMove].bind(this), 16));
     this[_board].on('moveEnd', this[_handleMoveEnd].bind(this));
-    this[_board].on('hover', time.throttle(this[_handleHover].bind(this), 32));
   }
 
   private [_handlePoint](point: TypePoint): void {
@@ -269,7 +270,7 @@ class Core {
         // Controll Element-Wrapper
         this[_mode] = Mode.SELECT_ELEMENT_WRAPPER_DOT;
         this[_selectedDotDirection] = direction;
-        this[_selectedUUID] = uuid;
+        this[_tempData].set('selectedUUID', uuid);
       } else {
         const [index, uuid] = this[_element].isPointInElement(point, this[_data]);
         if (index >= 0) {
@@ -285,7 +286,7 @@ class Core {
           this[_mode] = Mode.SELECT_ELEMENT;
         } else {
           // Controll Area
-          this[_selectedUUIDList] = [];
+          this[_tempData].set('selectedUUIDList', []);
           this[_mode] = Mode.SELECT_AREA;
         }
       }
@@ -296,7 +297,7 @@ class Core {
 
   private [_handleMoveStart](point: TypePoint): void {
     this[_prevPoint] = point;
-    const uuid = this[_selectedUUID];
+    const uuid = this[_tempData].get('selectedUUID');
 
     if (this[_mode] === Mode.SELECT_ELEMENT_LIST) {
       // TODO
@@ -316,16 +317,16 @@ class Core {
 
   private [_handleMove](point: TypePoint): void {
     if (this[_mode] === Mode.SELECT_ELEMENT_LIST) {
-      this[_dragElements](this[_selectedUUIDList], point, this[_prevPoint]);
+      this[_dragElements](this[_tempData].get('selectedUUIDList'), point, this[_prevPoint]);
       this[_draw]();
       this[_cursorStatus] = CursorStatus.DRAGGING;
-    } else if (typeof this[_selectedUUID] === 'string') {
+    } else if (typeof this[_tempData].get('selectedUUID') === 'string') {
       if (this[_mode] === Mode.SELECT_ELEMENT) {
-        this[_dragElements]([this[_selectedUUID] as string], point, this[_prevPoint]);
+        this[_dragElements]([this[_tempData].get('selectedUUID') as string], point, this[_prevPoint]);
         this[_draw]();
         this[_cursorStatus] = CursorStatus.DRAGGING;
       } else if (this[_mode] === Mode.SELECT_ELEMENT_WRAPPER_DOT && this[_selectedDotDirection]) {
-        this[_transfromElement](this[_selectedUUID] as string, point, this[_prevPoint], this[_selectedDotDirection] as TypeHelperWrapperDotDirection);
+        this[_transfromElement](this[_tempData].get('selectedUUID') as string, point, this[_prevPoint], this[_selectedDotDirection] as TypeHelperWrapperDotDirection);
         this[_cursorStatus] = CursorStatus.DRAGGING;
       }
     } else if (this[_mode] === Mode.SELECT_AREA) {
@@ -336,7 +337,7 @@ class Core {
   }
 
   private [_handleMoveEnd](point: TypePoint): void {
-    const uuid = this[_selectedUUID];
+    const uuid = this[_tempData].get('selectedUUID');
     if (typeof uuid === 'string') {
       const index = this[_element].getElementIndex(this[_data], uuid);
       const elem = this[_data].elements[index];
@@ -363,15 +364,15 @@ class Core {
     } else if (this[_mode] === Mode.SELECT_AREA) {
       const uuids = this[_helper].calcSelectedElements(this[_data]);
       if (uuids.length > 0) {
-        this[_selectedUUIDList] = uuids;
-        this[_selectedUUID] = null;
+        this[_tempData].set('selectedUUIDList', uuids);
+        this[_tempData].set('selectedUUID', null);
       } else {
         this[_mode] = Mode.NULL;
       }
       this[_helper].clearSelectedArea();
       this[_draw]();
     }
-    this[_selectedUUID] = null;
+    this[_tempData].set('selectedUUID', null);
     this[_prevPoint] = null;
     this[_cursorStatus] = CursorStatus.NULL;
     this[_mode] = Mode.NULL;
@@ -381,8 +382,17 @@ class Core {
     if (this[_mode] === Mode.SELECT_AREA) {
       this[_board].resetCursor();
     } else if (this[_cursorStatus] === CursorStatus.NULL) {
-      const cursor = this[_mapper].judgePointCursor(point, this[_data]);
+      const { cursor, elementUUID } = this[_mapper].judgePointCursor(point, this[_data]);
       this[_board].setCursor(cursor);
+      if (elementUUID) {
+        const index: number | null = this[_helper].getElementIndexByUUID(elementUUID);
+        if (index !== null && index >= 0) {
+          const elem = this[_data].elements[index];
+          if (elem) {
+            this[_coreEvent].trigger('mouseOverElement', { index, uuid: elem.uuid, element: elem, })
+          }
+        }
+      }
     }
   }
 
@@ -421,7 +431,7 @@ class Core {
       this[_coreEvent].trigger('changeScreen', {
         ...this[_board].getTransform(),
         ...{
-          selectedElementUUID: this[_selectedUUID]
+          selectedElementUUID: this[_tempData].get('selectedUUID')
         }
       });
     }
diff --git a/packages/core/src/lib/core-event.ts b/packages/core/src/lib/core-event.ts
index 99feae7..fab1314 100644
--- a/packages/core/src/lib/core-event.ts
+++ b/packages/core/src/lib/core-event.ts
@@ -13,6 +13,8 @@ export type TypeCoreEventSelectBaseArg = {
 
 export type TypeCoreEventArgMap  = {
   'error': any;
+  'mouseOverElement': TypeCoreEventSelectBaseArg & { element: TypeElement<keyof TypeElemDesc> }
+  'mouseLeaveElement': void;
   'screenSelectElement': TypeCoreEventSelectBaseArg & { element: TypeElement<keyof TypeElemDesc> }
   'screenMoveElementStart': TypeCoreEventSelectBaseArg & TypePoint,
   'screenMoveElementEnd': TypeCoreEventSelectBaseArg & TypePoint,
diff --git a/packages/core/src/lib/mapper.ts b/packages/core/src/lib/mapper.ts
index b15a2ec..ef75920 100644
--- a/packages/core/src/lib/mapper.ts
+++ b/packages/core/src/lib/mapper.ts
@@ -37,10 +37,14 @@ export class Mapper {
     return false;
   }
 
-  judgePointCursor(p: TypePoint, data: TypeData): TypePointCursor {
+  judgePointCursor(p: TypePoint, data: TypeData): {
+    cursor: TypePointCursor,
+    elementUUID: string | null,
+  } {
     let cursor: TypePointCursor = 'auto';
+    let elementUUID: string | null = null;
     if (!this.isEffectivePoint(p)) {
-      return cursor;
+      return { cursor, elementUUID};
     }
     const [uuid, direction] = this[_helper].isPointInElementWrapperDot(p);
     if (uuid && direction) {
@@ -85,13 +89,22 @@ export class Mapper {
           break;
         }
       }
+      if (uuid) {
+        elementUUID = uuid;
+      }
     } else {
-      const [index] = this[_element].isPointInElement(p, data);
+      const [index, uuid] = this[_element].isPointInElement(p, data);
       if (index >= 0) {
         cursor = 'move';
       }
+      if (uuid) {
+        elementUUID = uuid;
+      }
     }
-    return cursor;
+    return {
+      cursor,
+      elementUUID,
+    };
   }
 
 }
diff --git a/packages/core/src/lib/temp.ts b/packages/core/src/lib/temp.ts
new file mode 100644
index 0000000..a3e2890
--- /dev/null
+++ b/packages/core/src/lib/temp.ts
@@ -0,0 +1,36 @@
+
+type TempDataDesc = {
+  selectedUUID: string | null,
+  selectedUUIDList: string[],
+  hoverUUID: string | null,
+}
+
+
+export class TempData {
+
+  private _temp: TempDataDesc
+
+  constructor() {
+    this._temp = {
+      selectedUUID: null,
+      selectedUUIDList: [],
+      hoverUUID: null,
+    }
+  }
+
+  set<T extends keyof TempDataDesc >(name: T, value:  TempDataDesc[T]) {
+    this._temp[name] = value;
+  }
+
+  get<T extends keyof TempDataDesc >(name: T): TempDataDesc[T] {
+    return this._temp[name];
+  }
+
+  clear() {
+    this._temp = {
+      selectedUUID: null,
+      hoverUUID: null,
+      selectedUUIDList: [],
+    }
+  }
+}
\ No newline at end of file
diff --git a/packages/core/src/names.ts b/packages/core/src/names.ts
index bfff74f..c103371 100644
--- a/packages/core/src/names.ts
+++ b/packages/core/src/names.ts
@@ -7,8 +7,7 @@ const _element = Symbol('_element');
 const _helper = Symbol('_helper');
 const _hasInited = Symbol('_hasInited');
 const _mode = Symbol('_mode');
-const _selectedUUID = Symbol('_selectedUUID');
-const _selectedUUIDList = Symbol('_selectedUUIDList');
+const _tempData = Symbol('_tempData');
 const _prevPoint = Symbol('_prevPoint');
 const _draw = Symbol('_draw');
 const _selectedDotDirection = Symbol('_selectedDotDirection');
@@ -29,7 +28,7 @@ const _cursorStatus = Symbol('_cursorStatus');
 
 export {
   _board, _data, _opts, _config, _renderer, _element, _helper, _hasInited,
-  _mode, _selectedUUID, _selectedUUIDList, _prevPoint, _draw,
+  _mode, _tempData, _prevPoint, _draw,
   _selectedDotDirection, _coreEvent, _mapper, _initEvent, _handlePoint,
   _handleMoveStart, _handleMove, _handleMoveEnd, _handleHover, _dragElements,
   _transfromElement, _emitChangeScreen, _emitChangeData, _onlyRender, _cursorStatus,