Waveform control is beneficial to improve the quality of AC submerged arc welding,but it has very high requirements for polarity switching speed,zero-crossing arc stability and dynamic response speed of submerged arc welding power supply,especially in the condition of large current AC submerged arc welding pulse implementation is extremely difficult. Therefore,two optimal control strategies for high power AC pulse submerged arc welding power supply are proposed in this paper,including:the critical through strategy of secondary inverter,which can accelerate the polarity switching speed of AC output;PI separated control algorithm can improve the performance of dynamic waveform output of welding power source.The effectiveness of the proposed optimal control strategy is analyzed by modal analysis and SMIULINK model simulation method. Finally,the proposed optimization strategy is verified by experiments on the developed high-power AC pulse submerged arc welding power supply system. The results show that the proposed waveform control strategy can effectively improve the polarity switching speed of submerged arc welding power supply,and can well suppress the current overshoot,steady-state error and waveform oscillation of complex waveform.