Based on the problem of power signal output instability in the process of contactless grid connected power supply of photovoltaic power generation system, an automatic control method of contactless grid connected power supply is proposed. Firstly, the corresponding hardware equipment, including controller, inverter and driving equipment, is installed in the photovoltaic power generation system and grid connected power supply line. Secondly, the power supply transmission link is formed by non-contact grid connected way. The current signal and voltage signal in the power supply system are automatically monitored by the installed hardware equipment. Based on the monitoring results, the current balance and voltage balance of grid connected power supply are respectively in the two aspects of maximum power supply. The automatic control of grid connected power supply of photovoltaic power generation system is realized. In order to test the performance of the design control method, the experimental results show that the non-contact grid connected power supply automatic control method of photovoltaic power generation system can reduce the floating range of supply current and voltage.