Abstract
A theory of knowledge-based diagnostic reasoning is studied Based on the konwledge-based diagnostic reasoning and the experience of the diagnosis experts, the production rule and frame-expresssion are used in the system. The software is designed by Visual Basic.NET and Access. This system has collected fault code, data flow analysis, inspection method of ignition system and so on, the user can add,delete,alter and inquire conveniently. The system can offer the general maintenance methods for common troubles,and then arrange them in an order according to the trouble incidence，guiding maintenance，The system can add the steps of over-hauling,and expand the knowledge base．
