Abstract: Aiming at the problem of high-frequency common-mode leakage current in traditional un-isolated photovolatic grid-connected inverter,a novel single-phase un-isolatded photovoltaic grid-connected inverter is proposed,in which two continuous-current loops are set up. The common-mode voltage is held constant by clamping it to the half of the DC bus voltage during the continuous phase of the grid-connected current so as it leads to the reduction of the leakage current. In addition a PWM modulation strategy applied to the circuit is presented to reduce the harmonic component of output current. Finally,the Matlab/Simulink model and DSP experimental platform are established. Both simulation and experiement results show the performance of the novel single-phase un-isolated photovoltaic gridconnected inverter on the suppression of THD and leakage current.