The present invention discloses a liquid crystal display having touch function and a touch detection method thereof. The liquid crystal display comprises a display module and a touch module, and the display module and the touch module share a common electrode. The display module sequentially executes a plurality of operations of gate drive and gray scale drive in each frame. The touch module executes operations of touch detection as the display module executes a present operation of gate drive and gray scale drive and a voltage of the common electrode is in stable. With the aforementioned arrangement, the present invention is capable of reducing the interference of the display signals and the touch signals to improve the display quality and touch effect.