Electro hydraulic servo control system is one of the eight subsystems in the TRT device. According to the main control room instruction, to achieve the TRT open, stop, speed control, power control, control of top pressure and process test system, to achieve the above functions of the system control, and ultimately will be reflected in the control of turbine speed, it is necessary to control the turbine stator vane opening, and the opening of the static control the means of the electro-hydraulic position servo system. The precision and error of the control system directly affect the process control of each stage of TRT system. Thus, the position and function of the system in TRT is very important.