diff --git a/src/map/Map.js b/src/map/Map.js
index 5fa9ead1e..6f66ab845 100644
--- a/src/map/Map.js
+++ b/src/map/Map.js
@@ -783,9 +783,10 @@ class Map extends Handlerable(Eventable(Renderable(Class))) {
     /**
      * Caculate the zoom level that contains the given extent with the maximum zoom level possible.
      * @param {Extent} extent
-     * @return {Number} zoom fit for the extent
+     * @param  {Boolean} isFraction - can return fractional zoom
+     * @return {Number} zoom fit for scale starting from fromZoom
      */
-    getFitZoom(extent) {
+    getFitZoom(extent, isFraction) {
         if (!extent || !(extent instanceof Extent)) {
             return this._zoomLevel;
         }
@@ -801,7 +802,7 @@ class Map extends Handlerable(Eventable(Renderable(Class))) {
             scaleY = size['height'] / h;
         const scale = this.getSpatialReference().getZoomDirection() < 0 ?
             Math.max(scaleX, scaleY) : Math.min(scaleX, scaleY);
-        const zoom = this.getZoomForScale(scale);
+        const zoom = this.getZoomForScale(scale, null, isFraction);
         return zoom;
     }
 
diff --git a/test/map/MapSpec.js b/test/map/MapSpec.js
index 0e57a072e..4be2dd38d 100644
--- a/test/map/MapSpec.js
+++ b/test/map/MapSpec.js
@@ -330,6 +330,14 @@ describe('Map.Spec', function () {
             expect(fitZoom).to.eql(zoom + 3);
         });
 
+        it('getFitZoom return fractional', function () {
+            var extent = map.getExtent();
+            var zoom = map.getZoom();
+            var fitZoom = map.getFitZoom(extent, null, true);
+
+            expect(fitZoom).to.eql(zoom);
+        });
+
         it('fit to extent without animation', function () {
             var extent = new maptalks.Marker(map.getCenter()).getExtent();
             var maxZoom = map.getMaxZoom();