Abstract: Digital twin is a technology to realize the mapping of a physical system to a digital model of the information space. It is listed as one of the six cutting edge technologies in the future national defense and aerospace industry. It is also expected to play an important role in the advanced nuclear energy systems such as the intelligent control of a nuclear power plant, the space reactor, the small module reactor, etc. In recent years, some countries have launched projects to develop digital twin technology for the nuclear reactors, with the goal of reducing their operation and maintenance costs of the nuclear power plants significantly. The research and development of digital twin systems for space nuclear power and lunar-based nuclear power devices has also received attention. This article comprehensively describes the research status and development directions of the digital twin technology in the field of the advanced nuclear energy. It proposes a multi-dimensional evaluation digital model suitable for nuclear reactors, initially builds an error diagnosis process, and discusses the key technology and the potential application of digital twin in the field of the advanced nuclear energy.