Abstract: This application discloses a compensation circuit and method for potential induced degradation, a power module, and a photovoltaic system. The compensation circuit includes a switch, a first resistor, and a controller. The switch and the first resistor are connected in series, a first end of the compensation circuit is connected to a positive output end PV+ of a photovoltaic module, and a second end of the compensation circuit is connected to a second end of a first DC-DC converter. The controller is configured to control the switch to be closed when output voltage of the photovoltaic module is less than preset voltage, so that the first DC-DC converter provides electric energy of the battery to the second end of the compensation circuit. A second resistor is connected between the positive output end PV+ and a negative output end PV? of the photovoltaic module.