Abstract: Based on the statistics of the troubles that happened in a given engine including their times,the appearances,the reasons,the characters,as well as the measure and the time for eliminating,quantitative analyses of the troubles have been made,and the variable relationships of the trouble-frequency with engine sample,engine operation time section and properties of the trouble have been found out.The monographic analysis has been focussed on the repeated failure and major failure.The reliability and maintainability index of the given engine have been evaluated.Finally,precautions during field maintenance are discussed,some suggestions are presented for its modification and production.