Disclosed is a flyback converter with a synchronous rectifier, in which the synchronous rectifier includes a synchronous switch, a current transformer connected in series between a drain terminal of the synchronous switch and an output terminal, and a secondary synchronous rectification driver connected to the gate terminal of the synchronous switch. Furthermore, a shunt resistor is connected in parallel with the current transformer for providing a current bypass path for a secondary current flowing through the synchronous switch and the current transformer, and thereby reducing the current flowing through the current transformer. Thus, the overall efficiency of the flyback converter can be enhanced and the life of the current transformer can be prolonged.