A startup circuit for an auxiliary power supply of a photovoltaic inverter, wherein: the startup circuit, a capacitor of a direct current bus bar, an auxiliary power supply of the photovoltaic inverter, and at least one solar panel are all connected in parallel between positive and negative electrodes of a direct current bus bar, and the at least one solar panel supplies power to the auxiliary power supply through the capacitor of the direct current bus bar; and the startup circuit comprises: a power absorbing circuit, wherein the power absorbing circuit is connected in parallel between the positive and negative electrodes of the direct current bus bar, and the power absorbing circuit is configured to absorb power that is output by the at least one solar panel to the direct current bus bar; and a startup control circuit, wherein the startup control circuit is connected in parallel between the positive and negative electrodes of the direct current bus bar; and characterized in that the power absorbing circuit is configured to stop absorbing the power that is output by the at least one solar panel to the direct current bus bar, when a maximum power point MPP of the at least one solar panel is greater than or equal to startup power of the auxiliary power supply; and the startup control circuit is configured to start up the auxiliary power supply when the power absorbing circuit is turned off and the capacitor of the direct current bus bar is charged to a first voltage, wherein the first voltage is corresponding to an output voltage of the at least one solar panel when the output power of the at least one solar panel is greater than the startup power of the auxiliary power supply. the startup circuit, a capacitor of a direct current bus bar, an auxiliary power supply of the photovoltaic inverter, and at least one solar panel are all connected in parallel between positive and negative electrodes of a direct current bus bar, and the at least one solar panel supplies power to the auxiliary power supply through the capacitor of the direct current bus bar; and the startup circuit comprises: a power absorbing circuit, wherein the power absorbing circuit is connected in parallel between the positive and negative electrodes of the direct current bus bar, and the power absorbing circuit is configured to absorb power that is output by the at least one solar panel to the direct current bus bar; and a startup control circuit, wherein the startup control circuit is connected in parallel between the positive and negative electrodes of the direct current bus bar; and a power absorbing circuit, wherein the power absorbing circuit is connected in parallel between the positive and negative electrodes of the direct current bus bar, and the power absorbing circuit is configured to absorb power that is output by the at least one solar panel to the direct current bus bar; and a startup control circuit, wherein the startup control circuit is connected in parallel between the positive and negative electrodes of the direct current bus bar; and characterized in that the power absorbing circuit is configured to stop absorbing the power that is output by the at least one solar panel to the direct current bus bar, when a maximum power point MPP of the at least one solar panel is greater than or equal to startup power of the auxiliary power supply; and the startup control circuit is configured to start up the auxiliary power supply when the power absorbing circuit is turned off and the capacitor of the direct current bus bar is charged to a first voltage, wherein the first voltage is corresponding to an output voltage of the at least one solar panel when the output power of the at least one solar panel is greater than the startup power of the auxiliary power supply.