The invention discloses a flyback circuit, comprising a primary coil end circuit and a secondary coil end circuit; the secondary coil end circuit includes a secondary coil coupled to a load circuit; the primary coil end circuit includes a switch element, first primary coil N1 serially connected between a positive pole of a direct-current power source and a ground, an energy-storage element and a secondary primary coil; the switch element is coupled between a joint of the first primary coil and the energy-storage element, and the ground, and is used for receiving a PWM (pulse width modulation) signal to achieve periodic make and break; the energy-storage element stores leakage inductance energy of the flyback circuit when the switch element is off; when the switch element is on, the stored leakage inductance energy is released to the load circuit of the secondary coil end circuit. The invention also provides an electronic device. The electronic device and the flyback circuit can absorb and utilize leakage inductance energy generated by the flyback circuit effectively, and energy utilization rate is increased.