Abstract: An electronic device and a gravity sensing calibration method thereof are provided. The electronic device includes a gravity sensing unit, an image capturing unit and a processing unit. The gravity sensing unit recognizes a rotating direction of the electronic device according to default gravity reference data. The image capturing unit captures an image with an object. The processing unit obtains a current gravity sensing value through the gravity sensing unit and generates specific gravity reference data according to the current gravity sensing value. The processing unit analyzes the image to determine a moving direction of the object relative to the electronic device, so as to recognize the rotating direction of the electronic device according to the specific gravity reference data and the moving direction of the object.