The paper is to develop a new approach to analyze the reliability of pressure-reducing valve basing on commercial software Ansys. After introducing the work principle of the pressure-reducing valve containing membrane, the mechanical model of the membrane acted by pressure caused by turbulence is established, base on which the simulated model built in Ansys is made. For the stress response of the membrane is dealt as linear response, so the loads acting on the membrane which consist of two parts, one is constant pressure, and another is harmonic load, are taken as superposition of two parts, and the stress response can be taken as superposition of two kinds of cases in Ansys, that are static analysis and harmonic analysis. Then by mote simulation the statistical character of the stress response can be obtained, such as mean and variance. Using three- parameter S-N equation and constant life fatigue life curve, the equation of the equivalent mean fatigue life is established, basing on the equation and linear cumulative damage theory, the fatigue reliability during certain period can be gotten. At last an example is given to verify above approach.