Abstract: The large flux pressure reducing valve (PRV) is a key part of the aircraft ground testing system. The problem of outlet pressure rise of the PRV is tackled in this paper by modeling analysis, control system design and experimental verification. First, the force analysis of the PRV kinetic components is conducted, which is utilized to establish the steady working model. It is observed from the expression that the sustaining decrease of the inlet pressure can cause the rise of the outlet pressure and the influence factors of the PRV outlet pressure is obtained. This problem can be solved by adjusting the control chamber pressure. Second, the control system framework is constructed based on Programmable Logic Controller (PLC). The outlet pressure feedback control is conducted by acquiring the outlet pressure signal via sensors and adjusting control chamber pressure using the booster jar with high-speed solenoid valves. At last, a series of long-term experiments of 30~60 seconds are designed to test the feasibility of the control system at a large mass flow rate of 16~27kg/s. Results show that this control system effectively stabilizes the outlet pressure and successfully solves the outlet pressure rise problem in the testing process.