Abstract: Focused on many problems existing in pressure control system of drilling pipe friction welding,such as high failure rate and poor amenability,the basic principles of friction welding and electro-hydraulic proportional technique were briefly described.The application of electro-hydraulic proportional technique in pressure control system on friction welding was discussed also.The pressure is controlled in closed loop for this system and the feed speed of slide is controlled in opened loop;and real-time examination can detect the main spindle speed,axial pressure,axial abbreviated volume,current and oil temperature of principle motor.According to the data of the practical production,this system is suited to the pressure control system of the practical production.