The harmonic reducer is a new type of reducer, developed on the theoretical basis of harmonic gearing technology, the harmonic reducer was first used in the field of aerospace technology. Simulation and analysis of harmonic reducer dynamics is an essential direction in the field of harmonic reducer research; through the use of three-dimensional modelling software SolidWorks and mechanical system dynamics simulation software ADAMS, the establishment of harmonic reducer transmission parts the three-dimensional solid simulation model, discusses the model establishment method and the simulation process, the study of the flexible wheel and the rigid wheel change force rule, to explore in the flexible wheel and the rigid wheel mesh stiffness and the mesh damping of a specific condition, the wave generator length of the long axis and the short axis of the length of the change rule of the impact of the mesh force change rule, to provide a basis for the harmonic speed reducer research.