There is provided an interactive system, which includes a remote controller. The remote controller is equipped with a camera to capture an operating frame having a user image and a background image therein; and a processing unit to analyze the operating frame to identify a user image section and a background image section within the operating frame corresponding to the user image and the background image respectively, wherein the processing unit generates a movement information of the remote controller according to intensity distributions of the user image section and the background image section.