Since the advent of machinery, the corresponding mechanical parts. But as a discipline, mechanical parts are separated from mechanical tectonics and mechanics. With the development of the mechanical industry, the new design theory and method, new materials and the emergence of the process, mechanical parts have entered a new stage of development. The theory of finite element method, fracture mechanics, elastic hydrodynamic lubrication, optimization design, reliability design, CAD (CAD), Solid Modeling (Pro, Ug, SolidWorks, etc.), system analysis and design methodology have been gradually used in the research and design of mechanical parts. It is an important trend in the development of this discipline to better realize the integration of various disciplines, to combine macro and micro, to explore new principles and structures, to use the dynamic design and precise design, to make more effectively using electronic computers, and to further develop the design theory and methods.