Abstract: Elaborated here in the paper are two control systems for the pipe friction stir welding machine,i.e.,the system constructed with the S7-300 series PLC and servo system,and the system composed by the CNC system and the servo system.Both are used in the pipe welding process to fulfill the precise closed-loop control of the stirring head(spindle motor),the synchronous rotating frame(the rotation motor)and the stirring head feeding(the feeding motor),and furthermore to continuously adjust and optimize the control parameters,and improve the algorithm for control of the coordination of the movements among the motor shafts.The separate advantages and disadvantages of each of the said two control systems are compared,and the control process of the first one is elaborated and emphasized.