Abstract: As a typical high-tech product, it is a challenging task to reproduce and predict the behavior and state of the physical entity of aircraft. As the link between physical world and virtual world, digital twin technology can express aircraft in virtual space with high precision, high real-time and high integration, so as to promote the in-depth study of aircraft. This paper discusses the core technologies of digital twin, such as complex product model building technology, information physical fusion technology, data collection and transmission technology, big data technology, etc. This paper focuses on the main application of information physical fusion technology in digital twin technology. In the field of aircraft, digital twin is applied in the whole life cycle of aircraft, such as design verification, manufacturing and assembly, health monitoring and maintenance. Finally, the difficulties of digital twin technology are briefly analyzed.