This paper presents a method to realize flexible adaptation of welding controllers to different industrial bus. Firstly,a standard Modbus RTU bus protocol interface is developed on the welding control board,and then Modbus RTU bus is adapted to different bus interfaces（such as ProfiNet,ProfibusDP,CC,L,ink,DeviceNet,EtherNet） by bus conversion module. At the same time,bus conversion module is adapted to different bus interfaces through pin form. It can flexibly change the bus interface to connect the welding controller to different industrial bus,and lay the foundation for automatic welding in the welding workshop of automobile factory.