Abstract: Aiming at the leakage current of non-isolated photovoltaic（PV）power generation system,a five switch non-isolated singlephase grid-connected PV inverter with low leakage current is proposed. One of the switches has a high-frequency on-off to obtain a DC pulse,and the other four switches are divided into two groups. They are alternately connected with the grid frequency to change the current direction,so that the inverter can be connected to the grid. The circuit topology is freewheeling through the high performance diode. By analyzing the leakage current of the PV inverter,it indicates that the grid side is isolated from the DC side in the freewheeling phase,so that the two ends of the parasitic capacitance do not contain high frequency components,and the leakage current can be limited to within ±20 mA. Simulation and experimental results show that the topology can effectively suppress the leakage current of single-phase grid-connected PV inverters.