The stability of pressure control of proportional relief valve has a significant influence on the loading characteristics and pressure limiting characteristics of hydraulic system.A certain type of proportional relief valve was studied based on mathematical model and numerical simulation.Experiments were also performed to verify the accuracy of the mathematical model.By analyzing the influence of the volume of spring cavity in main valve and the diameter of the orifice in pilot valve on pressure control stability of the proportional relief valve,it provides guidance for further optimized design and engineering application of proportional relief valve.