Abstract: Based on the analysis of the characteristic of aeroengine early fault and information fusion,a method of forming the basic belief function was proposed when evidence theory was applied to information fusion of aeroengine fault symptom level.Thus,more precise early fault symptom could be attained.Moreover,the acquired fault symptom was applied to fuzzy cluster analysis to obtain aeroengine fault sources.Furthermore,the proposed method used fuzzy measure to express fault symptom,and considered the characteristics of imprecision,uncertainty and ambiguity of aeroengine early fault symptom.This is more suitable for the practical situation of aeroengine early fault.