Knowledge representation is one of the key technologies in the designed expert system.According to the requirement of total design of motorcycle, this paper researches the classificationof knowledgeand experienceof the motorcycle, analyses the points of knowledge representationmethod such as production rule, frameworkand object-oriented and so on, and puts forward the object-oriented knowledge representation method which is combined with abstraction, encapsulationand inheritanceof object-oriented technique. At last the authors realizes the knowledge representation of motorcycle designing under the language environmentof C++ and givesthe knowledge representationexamples of motorcyclebodywork designing.