Abstract: In order to meet the new standard requirement of reactive power,this paper proposed a novel reactive power modulation for non-isolated H6 bridge type single-phase photovoltaic grid-connected inverter. The mechanism for grid current distortion of H6-type inverter in current zero-crossing point and voltage zero-crossing point, when it is running in the mode of reactive power compensation, was analyzed. The proportion-integration-resonance（PIR） current controller was used for restraining DC component in grid current. As to suppress the current zero-crossing distortion and improve the waveform of grid current, global sliding mode function based on PIR was constructed, and the control law of global sliding mode was derived. Finally, 5k V?A experiment system of single-phase photovoltaic grid-connected inverter is built to validate the availability of the proposed modulation method and waveform-improving control strategy.