The stability of the outlet pressure of the pressure reducing valve is an important factor affecting the overall performance of the valve, and it is particularly important to design the valve reasonably in the development stage. The pressure stability test system was designed by combining the hydraulic system and the measurement and control system,by which the outlet pressure of the valve could be accurately collected. LabVIEW software and data collector were combined as a data collection platform to realize realtime acquisition and display of current, pressure and other data. The results show that the test system can be used to well monitor the fluctuation of the outlet pressure, which provides reference for the design and life detection of the proportional pressure reducing valve.