Abstract: A four times frequency IGBT 300KHz induction welding power is put forward.Power control is composed with three-phase diode bridge inverter and DC chopper circuit.The chopper circuit adopts active nondestructive buffer buck converter, and in a wider range of the load the main, deputy switch tube and free-wheeling diode are achieve soft switch.The four groups of IGBT inverter in parallel are used for each IGBT in time-sharing control.The work frequency of the inverter is four times of the frequency IGBT switch.The inverter works in the load resonant state, and the switch tube works in shutting off at ZCS and switching on and off at ZVS.The output 300 kHz/50 kW serial-resonant inductive welding power was designed, and the design parameters and test waveforms were given.The results show that it is possible to produce capacity of high frequency induction heat welding power by using the method of four-times frequency control points with IGBT alternative power MOSFET.