The invention discloses a single-phase photovoltaic grid-connected inverter which is composed of an inverter unit, a secondary power decoupling circuit and an output filter. The output filter is composed of two inductors and one capacitor. The secondary power decoupling circuit is composed of one energy storage inductor and two bidirectional power switches, wherein a bridge arm composed of the two bidirectional power switches is directly connected with the direct-current capacitor in parallel. The energy storage inductor stretches across between the bridge arm composed of the two directional power switches and a bridge arm composed of two blocking type bidirectional power switches. According to the single-phase photovoltaic grid-connected inverter, due to the fact that the secondary power decoupling circuit and the output filter are arranged, secondary ripple wave components in the voltage of the direct-current side can be effectively restrained, the service life of a photovoltaic array is prolonged, the quality of grid-connected currents is improved, and in addition, the needed direct-current filter capacitor is small. Thus, the size of a whole system is reduced, and cost is lowered.