Abstract: The relief valves used in aircrafts must keep functioning properly under initial rising time and vibration conditions. It is the focus to find an effective method for analyzing the performance of the relief valves and to build up the mathematical models under vibration condition. The results show that relief valve with balance piston has the function of anti-vibration, noise elimination and constant pressure, and the two-stage relief valve works in three important stages: the precursor relief valve opening stage, the main relief valve opening stage and normal working conditions. Vibration condition has great influence on the pressure characteristics of two-stage relief valve and the structure parameters decide the delay time and dynamic characteristics. The theoretical results are consistent well with the experimental results. The mathematical models of relief valve under vibration are useful for the production and development of new valve.