Abstract: To resolve the problems of the friction welding machine hydraulic systems with fixed displacement pump,such as large energy consumption,quick oil temperature rising and instability of welding pressure parameter,the energy-saving hydraulic system is developed,which includes the force applying system with the proportional variable displacement pump under the computer-controlled and the auxiliary system with the constant pressure variable displacement pump. The energy-saving principle of the new hydraulic system is analyzed,and the energy consumption performances of the two type hydraulic systems are tested. The results showed that under the same condition,the energy-saving hydraulic system could reduce energy consumption by 57% compared with the ordinary hydraulic system. The energy savings are very effective during the stages of pre-weld,friction and forge. The energy-saving hydraulic system has good features of higher energy efficiency,lower energy consumption and better energy saving,and has been used in industry.