Abstract: A multi-phase clock generation system and a clock calibration method thereof. The multi-phase clock generation system comprises an input module, a frequency division module and a control module. The input module inputs a reference clock signal with a clock period. The frequency division module according to the reference clock signal produces a phase clock signal with a frequency magnification relationship. The control module divides the phase clock signal into a plurality of clock intervals. There is a clock interval between two adjacent phase clock signals, and each of the plurality of clock intervals has a phase time delay. The control module controls a first phase clock signal of the plurality of phase clock signals to align with a last phase clock signal. The control module sequentially arranges each of the plurality of phase clock signals according to the phase time delay.