Abstract: By combining fuzzy control with incremental PID control, a fuzzy PID control system is designed for the liquid nitrogen refrigeration cryogenic test system with coordinated operation of double regulating valves. The state-space model of the controlled object is determined by the pre-test and the system identification, and the control system model is built for the simulation research. The simulation results show that compared with traditional PID control, the fuzzy PID control is faster in the adjustment time with better control accuracy. On this basis, experiments on a practical system are carried out to verify the feasibility of this method. Both the test and the simulation results prove the accuracy and stability of the control method, and such a method is easy to be transplanted to similar test systems, which is of guiding significance for the design of temperature control strategy in related applications.