The invention provides a power decoupling circuit for a photovoltaic grid-connected inverter, and relates to circuit devices of alternating-current main lines or alternating-current power distribution networks. The power decoupling circuit is composed of a filter capacitor, an inductor, a decoupling capacitor A, a decoupling capacitor B, a switch tube A and a switch tube B. The decoupling capacitor A is in parallel connection with the filter capacitor after being in series connection with the decoupling capacitor B, a collector of the switch tube A in series connection with the switch tube B is connected to a positive pole node of the part, in parallel connection with the filter capacitor, of the decoupling capacitor A in series connection with the decoupling capacitor B,, an emitter of the switch tube B in series connection with the switch tube A is connected to a negative pole node of the part, in parallel connection with the filter capacitor, of the decoupling capacitor A in series connection with the decoupling capacitor B, and an intermediate node enabling the decoupling capacitor A to be in series connection with the decoupling capacitor B is connected to the connecting point of an emitter of the switch tube A and a collector of the switch tube B through the inductor. The defects that an existing photovoltaic grid-connected inverter needs large-capacity and large-size decoupling capacitors and is complex in structure and high in cost are overcome.