With the rapid development of a new generation of information technology such as cloud computing, 3D CAD technology is becoming the platform foundation for product innovation design and digital design and manufacturing of manufacturing enterprises. This paper proposes research on the 3D CAD information systems integration based on a private cloud platform. Through studying the concept, characteristics and hierarchical structure of cloud computing. According to the manufacturing information application requirements, the system will publish and deploy corresponding application services according to user needs, and effectively solve the poor integration of some current information systems. Private cloud service platform. In view of the wide variety of 3D CAD software currently on the market, in the process of integrating with the manufacturing information system, a general integration framework design based on the cloud platform is proposed and standardized cloud service interface definitions are provided to extend the functions of the integration framework. Data differences between different CADs, and XML files with good scalability and data self-describing capabilities are used as intermediate files for information interaction. Through the entire business process, the technical application of engineering drawing into PDF, browsing and signing was introduced, and the correctness of the private cloud platform and integration technology was verified.