This study discusses the secondary development of the database of mechanisms based on the Creo platform, and introduces the key technologies in detail. In the environment of Visual Studio 2010, with the secondary development tools Creo/TOOLKIT provided by Creo software, combined with SQL Server database, it uses MFC technology to design and compile the database of mechanisms. All mechanisms are designed by top-down in the database of mechanism. Taking the design of planetary gear cam mechanism of closed planetary gear train as an example, the specific functions of the database of mechanisms are introduced. The engineering application shows that the system can retrieve mechanism fast, and can view the mechanism's motion simulation, motion curves, features, etc. At the same time, it can design the concrete mechanism rapidly, improve the level of product design, and shorten the design cycle.