The traditional FMECA is used to analyze the reliability of hydraulic system of amphibious armored vehicle.Because of many evaluation indexes，few fault data，it is difficult to have a accurate analysis.The fuzzy theory was introduced to the FMECA to form the fuzzy FMECA method, then the method was applied to the reliability analysis of the hydraulic system of amphibious armored vehicles.According to the results,the criticality of failure modes was ranked and the emphases of maintenance and reliability improvement were found.The analysis results show that the fuzzy FMECA method can help to find out the emphases of fault diagnosis and put forward improve measures to make the reliability improved.