A tracking system includes a trackable device and a tracking device. The trackable device has a three-dimensional shape. The trackable device includes a first orientation sensor for sensing a first orientation of the trackable device. The tracking device is communicated with the trackable device. The tracking device includes a second orientation sensor, an image sensor and a processing circuit. The second orientation sensor is configured to sense a second orientation of the tracking device. The image sensor configured to capture an image. The processing circuit is coupled with the second orientation sensor and the image sensor. The processing circuit is operable to calculate a two-dimensional silhouette corresponding to the three-dimensional shape according to the first orientation and the second orientation, and utilize the two-dimensional silhouette to search the image captured by the image sensor for allocating coordinates of the trackable device within the image.