The invention discloses a high-power interface circuit system based on a microcomputer, which comprises a controller, an interface circuit system connected with the controller through a bus driving interface board and an AC motor electrically connected with the interface circuit system through a main contactor, wherein the interface circuit system is composed of an input photoelectric coupler, a driving amplifier, an auxiliary contactor and an output photoelectric coupler; the driving amplifier is electrically connected with the input photoelectric coupler and the auxiliary contactor; and an output end of the auxiliary contactor is electrically connected with the main contactor. According to the high-power interface circuit system based on the microcomputer, the auxiliary contactor is driven by output current of an interface circuit, then the main contactor is controlled according to on-off of the auxiliary contactor; the controller judges whether a control signal is correct or not according to the on-off state of an auxiliary contact of the main contactor; and the whole controller controls the system to form a closed-loop control circuit, and the stability is good.