Disclosed is a LED display system and a control method thereof. The display system comprises a control card outputting clock signals and data signals; at least one driving circuit group, coupled with the control card, and each including a plurality of cascaded driving circuits, receiving a clock signal and a data signal and transmitting them among the plurality of driving circuits, wherein at least one stage of driving circuit in each driving circuit group comprises an inverter, which inverts the clock signal received by the current stage of driving circuit to obtain an inverted clock signal. The LED display system of the present disclosure can effectively avoid excessive attenuation of the clock signal in the cascaded driving circuits, ensure data sampling correctness based on the clock signal, and ensure display effect of the LED display screen.