Abstract: Pipeline welding is widely used in the laying of oil and gas pipelines on land and sea. In the construction process, manual welding and semi-automatic welding have low efficiency, high work intensity, which cannot guarantee welding quality. In order to solve the above problems, a pipeline automatic welding robot control system with STM32 as the control core and Modbus protocol as the system communication network was proposed to realize the integrated coordinated control of digital welding power supply, angle sensor, motion control, data acquisition and other functional units. The hardware design and software implementation of the control system’s hand controller, main control unit, data acquisition and processing unit were introduced. P-GMAW was used for welding experiments, and the results show that the composition and control strategy of the welding robot control system are reasonable and effective, the welding efficiency is high, and the welding seam is well formed.