This paper introduces a new method,case -based reasoning(CBR)and presents the composing,structu re,function and principle of the enterp rise crisis alert system based on case -based reasoning.A lot of critical tech-niques in the enterprise crisis alert system based on case -based reasoni ng are discussed.An example in cheat crisis alert is given to validate the algorithm.The results show that the method is effective.The research lays a fou ndation for further study of applying case -b ased reasoning for enterprise crisis alert system.