1. A gesture recognition method for an interactive system, the interactive system comprising at least one light source, a reflector, and an image sensor configured to capture an image window comprising object images of at least one pointer caused by the pointer occluding light emitted from the at least one light source or the reflector, the gesture recognition method comprising: capturing the image window with the image sensor; obtaining information of the object images in the image window; determining whether there is a plurality of pointers according to the information of the object images; and executing, when it is determined that there is a plurality of pointers, a gesture recognition according to a relation between the object images in successive image windows without calculating respective position coordinates of the object images, wherein the information of the object images comprises an average number of the object images, an average distance between the object images, and a greatest distance between the object images.