The rise of the Flexible Manufacturing System (FMS) and the Computer Integrated Manufacturing System (CIMS) put forward a more urgent need for the practical fixture design software. 3D Visual Basic-based standard parts library is proposed in this paper. By calling the Application Program Interface (API) functions of Solidworks as the secondary development, the 3D standard parts library is established. And then the application program is made as plug-in to hanging onto the menu of Solidworks operating environment. When the assembly design starts, users can select the standard parts they need by clicking Solidworks menu. And then the application program can automatically query all the data required for drawing pictures. Finally the 3D entities of standard parts are generated so that they can be adopted for the assembly environment.