The invention relates to an illumination system based on microwave sensing and a control method thereof. The illumination system based on microwave sensing includes a microwave sensing module, a microwave output control module, a micro processing unit and an illuminating element, wherein the microwave sensing module is controlled to collect microwave signals through a first pulse signal, and output of the microwave signals collected by the microwave sensing module is controlled through a second pulse signal; and the micro processing unit analyzes and processes the output microwave signals, andcontrols the illumination system. Compared with the prior art, the pulse power supply mode of the illumination system based on microwave sensing reduces the power consumption and the radiant power ofa microwave sensor, enables the product to pass the FCC certification, and guarantees stability of the output intermediate frequency signals by means of the timing design of the first pulse signal and the second pulse signal of the same pulse frequency.