Abstract: To achieve the goals of "Double Carbon" and "Less Copper and More Silicon",non-isolated inverters have been widely researched and applied in the field of photovoltaic new energy power generation. As the leakage current existing in the non-isolated photovoltaic grid-connected system is one of the key problems that need to be solved urgently,this paper proposes a new single-stage common ground-type non-isolated photovoltaic grid-connected inverter topology with no leakage current but high-efficiency. The working principle and mode of the front-stage DC-DC buck-boost circuit of the proposed inverter are analyzed,and the realization conditions of its soft switching are given. The internal mechanism of the new topology without leakage current is studied, and its output voltage characteristics are deduced. A simulation model based on PSIM software is built. The simulation results show that: compared with the traditional leakage current suppression topology,this topology can achieve no leakage current photovoltaic gridconnection,and the front-end DC-DC converter helps to realize soft switching,which can be used in high-efficiency and highquality electric energy grid-connection within a wide input voltage range.