The present invention provides an array substrate, a display apparatus and a driving method thereof. The array substrate comprises: an active area, comprising a plurality of display pixel units; a source driver, being located outside the active area and providing drive signals to the display pixel units; a gamma voltage generating circuit, providing a gamma reference voltage to the source driver, and the gamma voltage generating circuit is inputted with a PWM signal from the pulse generating circuit TCon and obtains the gamma reference voltage for outputting the gamma reference voltage to the source driver according to the PWM signal. Compared with the programmable control chip, the cost is diminished; compared with the resistance divider, the adjustment is convenient.