A ZVS (zero voltage switching) control circuit for controlling a flyback power converter includes: a primary side controller circuit for generating a switching signal, to control a primary side switch; and a secondary side controller circuit for generating a synchronous rectifier (SR) control signal for controlling a synchronous rectifier switch. The SR control signal includes an SR-control pulse and a ZVS pulse. The SR-control pulse controls the synchronous rectifier switch to perform secondary side synchronous rectification. The secondary side controller circuit determines a trigger timing point of the ZVS pulse according to a waveform characteristic of a ringing signal, to control the synchronous rectifier switch to be ON for a predetermined period, thereby achieving zero voltage switching of the primary side switch. The primary side or the secondary side controller circuit includes a jitter controller for performing jitter control on the ZVS pulse.