In the advanced manufacturing technology, how to integrate CAD/CAE software has become a very important research issue. After analyzing the function framework of collaborative design and simulation platform, the management model of collaborative design and simulation platform for numerical engineering is proposed in this paper. Moreover, workflow management technology, collaborative running management, collaborative development model database, database management, and Win32 API message interception technology are studied in detail. An object-oriented software integration method is presented. The method is divided into three lays: interface integration, data integration, and operation integration. A C/S structural prototyping system is developed by using C# and XML under .NET development environment. The system can support customizing engineering design and simulation task, which integrates various design and simulation tools, including some self-developed application tools.