diff --git a/src/ViewerCanvas.tsx b/src/ViewerCanvas.tsx
index 74623db..a511439 100644
--- a/src/ViewerCanvas.tsx
+++ b/src/ViewerCanvas.tsx
@@ -12,7 +12,7 @@ export interface ViewerCanvasProps {
   rotate: number;
   onChangeImgState: (width: number, height: number, top: number, left: number) => void;
   onResize: () => void;
-  onZoom: (targetX: number, targetY: number, direct: number, scale: number) => void;
+  onZoom: (targetX: number, targetY: number, direct: number) => void;
   zIndex: number;
   scaleX: number;
   scaleY: number;
@@ -102,7 +102,7 @@ export default class ViewerCanvas extends React.Component<ViewerCanvasProps, Vie
         x -= containerRect.left;
         y -= containerRect.top;
       }
-      this.props.onZoom(x, y, direct, .05);
+      this.props.onZoom(x, y, direct);
     }
   }
 
diff --git a/src/ViewerCore.tsx b/src/ViewerCore.tsx
index 960c74b..dfb0bd2 100644
--- a/src/ViewerCore.tsx
+++ b/src/ViewerCore.tsx
@@ -42,6 +42,7 @@ export default class ViewerCore extends React.Component<ViewerProps, ViewerCoreS
     onMaskClick: noop,
     changeable: true,
     customToolbar: (toolbars) => toolbars,
+    zoomSpeed: .05,
   };
 
   private prefixCls: string;
@@ -232,11 +233,11 @@ export default class ViewerCore extends React.Component<ViewerProps, ViewerCoreS
         break;
       case ActionType.zoomIn:
         let imgCenterXY = this.getImageCenterXY();
-        this.handleZoom(imgCenterXY.x, imgCenterXY.y, 1, 0.05);
+        this.handleZoom(imgCenterXY.x, imgCenterXY.y, 1, this.props.zoomSpeed);
         break;
       case ActionType.zoomOut:
         let imgCenterXY2 = this.getImageCenterXY();
-        this.handleZoom(imgCenterXY2.x, imgCenterXY2.y, -1, 0.05);
+        this.handleZoom(imgCenterXY2.x, imgCenterXY2.y, -1, this.props.zoomSpeed);
         break;
       case ActionType.rotateLeft:
         this.handleRotate();
@@ -289,6 +290,10 @@ export default class ViewerCore extends React.Component<ViewerProps, ViewerCoreS
     });
   }
 
+  handleScrollZoom = (targetX, targetY, direct) => {
+    this.handleZoom(targetX, targetY, direct, this.props.zoomSpeed);
+  }
+
   handleZoom = (targetX, targetY, direct, scale) => {
     let imgCenterXY = this.getImageCenterXY();
     let diffX = targetX - imgCenterXY.x;
@@ -549,7 +554,7 @@ export default class ViewerCore extends React.Component<ViewerProps, ViewerCoreS
           rotate={this.state.rotate}
           onChangeImgState={this.handleChangeImgState}
           onResize={this.handleResize}
-          onZoom={this.handleZoom}
+          onZoom={this.handleScrollZoom}
           zIndex={zIndex + 5}
           scaleX={this.state.scaleX}
           scaleY={this.state.scaleY}
diff --git a/src/ViewerProps.ts b/src/ViewerProps.ts
index 3ffc831..dbb7beb 100644
--- a/src/ViewerProps.ts
+++ b/src/ViewerProps.ts
@@ -59,6 +59,9 @@ interface ViewerProps {
 
   // custom toolbar
   customToolbar?: (toolbars: ToolbarConfig[]) => ToolbarConfig[];
+
+  // zoom speed
+  zoomSpeed?: number;
 }
 
 export default ViewerProps;