The utility model relates to a secondary side control power inverter, comprising an input circuit and at least one switching element. A primary side winding of a transformer, the voltage variation of which can change the on and off state of the switching element, is connected with the switching element, and a secondary side winding is arranged on the transformer. An output circuit is connected with the secondary side winding of the transformer, which is provided with an output end; a controller is positioned on the output circuit, which can sense the output voltage and tickle the corresponding voltage variation sensed to the primary side winding of the transformer; thus, the switching element can be controlled by the primary side winding of the transformer to make PWM or PFM switch motions in response to the motions.