Abstract: This paper proposes a visualized aeroengine fault diagnosis system mode based on self organizing topology map which combines vector quantization,fast clustering,information fuse and topology preservation,estimation of topographic error and quantization error is also given.And then this method is applied to aeroengine gas path fault diagnosis.The results show that this diagnosis mode is effective and rational.Furthermore,the paper has set up component visualized gray plane in which characteristics of fault vector,correlation of measured parameters and tendency of components can be observed easily,and also we can analyze inherence of faults by this approach.