The invention discloses a sliding mode direct voltage/power control method used for a photovoltaic grid-connected inverter. The sliding mode direct voltage/power control method comprises the following steps: establishment of a photovoltaic power generation system; signal measurement and processing; positive and negative sequence decomposition; calculation of Pg and Qg; calculation of Pg2 and Qg2; confirmation of control errors eu, eQ and eP; confirmation of sliding mode surfaces su and sQ; confirmation of control rate ucd and ucq; judgment of achieving of control objectives; alphabeta transform; and SVPWM modulation. The sliding mode direct voltage/power control method used for the photovoltaic grid-connected inverter has advantages of simple structure and high robustness. When power grid voltage is unbalanced, the control objectives of suppressing output power pulse of the grid-connected inverter and guaranteeing sinusoidal grid-connected three-phase current without waveform distortion can be realized respectively.