Abstract: In order to reduce the switching losses of the grid-connected inverters and improve system efficiency and current quality,this paper proposes a L+LCL type dual-frequency single-phase grid-connected inverter topology,which integrates a low switching frequency inverter unit and a high switching frequency rectifying unit. The low frequency unit is responsible for transmitting electric energy to the power grid. and the high frequency unit uses the feedforward compensation method to generate the harmonic elimination current. By this way,it does not need to extract the switching harmonics to suppress the current harmonics of the low frequency unit. The high-frequency unit uses the LCL filter to further reduce the high-frequency switching harmonics in the grid-connected current and improve the gridconnected current quality. The working principle and parameter design method of the inverter is proposed. The experimental test is carried out by using the prototype. The results show that the grid-connected inverter can guarantee the current quality,has good steadystate performance and dynamic response,and verify the efficiency advantage of the dual-frequency grid-connected inverter.