Abstract: In order to analyze the systematic reliability automatically,a model of fault transfer table for describing fault system is developed in two aspects:(1)the format of fault transfer table is improved obviously;(2)the energy flow fault class is put forward so as to supplement the fault transfer table.Using this ameliorated model,multi mode and complicated fault conjunctions can be described expediently.This model has been applied to fault description of an aeroengine hydraulic mechanical control system,and the fault tree has been built automatically,in result a success has been reached.