Abstract: Gas valve is one of the key components in ion source. In order to adjust the intake of gas, electrically driven operated system is widely used in the control of gas valve. The performance of gas valve control system directly affects the quality of the beams. SSC-LINAC ion source under construction adopted the advanced evaporative cooling technology. This ion source required the use of the motor to adjust two gas valves’ opening and to achieve precise position control and high reliability and stability. Adopting servo motor, the control system was designed which contained precise position control for the ion source. Now the control system has passed continuous operation test of three months and it runs well. Precise position precision can reach 0.3 degree.