The paper introduces the entirety design structure of distributed pipe welding control system. According to demand of pipe welding control, we design and achieve the DSP master control node of field-control layer. The DSP master control node is transplanted by DSP/BIOS operating system, and welding function modular is divided into several independent processes, which is controlled and scheduled. To enhance speed regulating scope and response time of rotation and wire feeding module of brush DC motor, we use feedforward-feedback control mode. Aim at particularity of pipe welding environment and variety of communication data type, the communication between field-management layer and field-control layer is CAN communication. We transplanted CAN-open protocol on it.