Abstract: In order to develop a single-supply servo amplifier driving electro-hydraulic valve,which can limit the amplitude of input voltage and output current,set zero,adjust gain,and monitor the position of valve core in real time,the amplifier circuit is designed according to technical indicators.Then the circuit model is simulated by using Multisim.PCB is manufactured and tested.Compared with the simulation results,it can be found that the developed servo amplifier meets the technical requirements,and its output current performs good linearity and wide adjustable range.