A touch detection system includes a stylus, a panel and a processing circuit. The panel can include a plurality of sensing cells used to receive a first signal and a second signal generated by a touch event. The processing circuit can be coupled to the panel and used to determine a plurality of first areas and a plurality of first intensities corresponding to the first signal, determine a plurality of second areas and a plurality of second intensities corresponding to a second signal, and determine whether the touch event is triggered by the stylus touching the panel according to the first intensities, first areas, the second intensities and the second areas.