In order to realize the synchronous improvement of quality， flexibility and efficiency of single piece and small-batch production of spacecraft， the connotation and development of digital twin technology are reviewed， and the basic model and dynamic evolution process of digital twin technology for spacecraft manufacturing system including product twin and production line twin are proposed. The realization method of digital twin in data acquisition， synchronous modeling， system evaluation and production line reconstruction is proposed， and the concrete realization way of virtual reality interaction mechanism by digital twin is expounded， and its validity is verified by practical application of spacecraft production.