The invention provides a photovoltaic microgrid inverter synchronous control device with a decision maker and a control method thereof, which belongs to the technical field of microgrid control. The control device is characterized in that the control device comprises a wireless standard time base circuit, and the output end of the wireless standard time base circuit is connected with the communication interface of a main control circuit. The control method comprises the steps that a wireless second base clock controller in a DSP main controller is used to generate a global synchronization time setting signal to adjust a triangular wave clock signal. The problem that controller output pulse cannot be instantaneously synchronized due to controller clock frequency difference is effectively solved. According to the invention, a decision compensation controller is used to evaluate fed back frequency and phase error to predict the adjustment trend of the frequency and phase of the output voltage of an inverter to acquire a control policy; fast synchronization of the output voltage of the inverter is realized; dynamic synchronization of the output voltage of different photovoltaic inverters distributed in a microgrid is realized; and transient circulation is restrained to promote stable and efficient operation of the microgrid.