This paper discusses the topology requirements of the small power photovoltaic grid-connected inverter,and introduces several typical topologies,moreover,points out the advantages and disadvantages,efficiency and applicable occasions of the various topologies. In this paper,a single-phase full-bridge grid-connected inverter topology(DC/AC) is designed. The soft-switching technology is employed on the topology for reducing switching loss. The topology can realizes zero voltage switching when the main switch turns on and turns off and zero current switching when auxiliary switch and the power diode turns on and turns off.The converter has higher efficiency than other topologies.