Based on the object-oriented technology,the model elements of a complicated mechanical system were analyzed according to their characteristics,and their class architecture in dynamic modelling platform to support dynamics simulation was presented.The two key technologies in the platform,i.e.managememt of relationship and subsystem modelling,were discussed.A simulation and modelling platform-InteDyn was developed using the above two technologies,and a car suspension and a full car models were built by the InteDyn,which validated the effectiveness and feasibility of the technologies.