Suppressing of leakage current has become an important technical issue for the non-isolated photovoltaic grid-connected system．Considering the importance of leakage current to the photovoltaic grid-connected system,in this paper,the resonant circuit of leakage current equivalent model is established firstly,the deficiency of traditional H4 topology is also pointed out,moreover,principles of the generation of leakage current are analyzed．Then,the paper proposes a novel inverter topology which can effectively suppress the leakage current,its working principles and control methods are analyzed respectively．Finally,a 2kW prototype of the inverter topology is set up to verify the theoretical analysis,experimental results verify that photovoltaic grid-connected inverter of this novel topology features better leakage current suppression.