With the gradual in-depth application of space technology in various industries, the spacecraft industry is ushering in a period of rapid development, and the product design and manufacturing are gradually presenting the characteristics of serialization and large scale production. In order to meet the development needs of on-site application of 3D drawings, planning management, production resource management, etc., we conceived and constructed the spacecraft AIT digital assembly system. Through continuous optimization and improvement, we successfully made the digital system able to guide the spacecraft AIT to smoothly execute processes according to the pre-defined procedures. The AIT digital assembly system undertakes the releases and displays of various data such as relevant process specifications, 3D models and process Boom tables from the 3D process design system. Besides, the digital system execution data can be fed back to the 3D process design system as the support for product status query, and the key data of system can be extracted to the data center system as the basis for production arrangement and management decisions. Finally, the AIT digital assembly system can interconnect with the material distribution, automatic container and access management systems, to establish multiple information channels.