In this paper, the principle of electro-hydraulic proportional control system are introduced, electro-hydraulic velocity control system are designed and can realize volevity control with high accuracy. In the system, relative amplitude abundant degree and phasic abundant degree and corresponding frequency of passing of Body system is easily obtained under different open ring gain of K, thus it is simple and accurate to choose reasonable parameters, and then can carry on smulation to system by Matlab/Simulink to examine the design results.