The invention discloses a full screen driven detection. A driving signal is simultaneously provided to all first conductive strips arranged in parallel in a first direction in a touch screen, and mutual capacitive signals are detected from all second conductive strips arranged in parallel in a second direction. The mutual capacitive signals can be used for determining whether an external conductive object coupled to the ground is touching or approaching the touch screen or not even if water or other conductive object not coupled to ground is on the touch screen. Thus, the baseline of the mutual capacitive signals can be updated if the touch screen is not touched or approached by any external conductive object coupled to ground over a predetermined period of time.