Abstract: To improve the modeling efficiency and reuse of models,subsystem modeling techniques for complex multi-body systems are addressed.A structure of subsystem supporting decomposition and reuse of models is proposed.Virtual parts are used to define the topological relationship among the subsystems,and main control parameters are introduced to encapsulate the design knowledge and the internal parameters in the subsystem.Consequently,a top-down hierarchical architecture of complex multi-body systems is constructed.Furthermore,in terms of the associated relationship among the main control parameters and the characteristic of the hierarchical architecture,an algorithm with high computational efficiency is presented to assemble the subsystems and solve the engineering constraints among the parameters.Finally,the procedure to model complex multi-body systems based on the proposed techniques is demonstrated through an example of truck modeling.