Abstract: A performance test system for electrohydraulic control valves has been develop-ed. lt is applicable for testing the characteristics of different kinds of servo, proportionalor P-Q valves. A design of reduced noise is established and measures for calibratingdata from analog signal channels utilizing those from digital chanels are adopted. Feedback regulation under constant differentia pressure is adopted in the hydraulic system.The test softwrare runs in a Windows enviroment.