A diagnosis method of aero-engine fault based on fuzzy inference and evidence theory was proposed in this paper.According to the fault symptoms

the proposed method inferred the probabilities of fault causes with experts' experience

so as to resolve the fuzzy problem of fault diagnosis.Then the results of fuzzy inference were regarded as basic probabilities of evidences to insure the veracity of evaluation.Finally

all evidences were aggregated and analyzed according to the combined rules to reduce the uncertainty of fault diagnosis and eliminate the inconsistency among evidences

so as to locate the fault cause accurately.The results of experiment show that the method is feasible and effective.