Abstract: The disclosure provides a microwave photon frequency synthesis system and method. In the disclosure, based on various combinations of path switching options of optical routing modules and electrical routing modules, the microwave photon frequency synthesis system is provided with a direct photoelectric conversion mode, an electrical frequency synthesis mode and an optical amplitude and phase control mode. The first optical signal frequency selection based on the optical frequency comb module and the frequency multiplication/division selection of the optical frequency multiplication/division module can be freely combined to realize frequency sources of various frequencies. Based on the optical frequency comb module to generate the first optical signal, and then combined with an electrical filtering module, phase noise can be reduced. The optical amplitude and phase may be controlled by the optical amplitude and phase control module.