A tracking system is provided. The tracking system comprises a trackable device which comprises a first illuminating module and the first illuminating module emits an infrared (IR) light and a tracking device which comprises an optical sensing module and a processor. The optical module is configured to sense an IR spectrum to capture a first image and sense a visible spectrum to capture a second image, and the IR light is in the IR spectrum. The processor is coupled to the optical sensing module. The processor is configured to search in the first image a first region corresponding to the IR light, locate in the second image a second region associated with the first region in the first image, and calculate a spatial status of the trackable device according to the second region in the second image.