Abstract: With the deepening of manned spaceflight and deep space exploration programs， the complexity and reliability requirements of space missions are increasing. The 3D simulation system in aerospace missions can provide an intuitive and convenient simulation analysis method for the exploration and engineering design of new aerospace technologies， and plays an important role in improving the reliability of aerospace missions. The continuous in-depth development of aerospace missions puts forward higher requirements for 3D simulation. The situation expression technology for space entities in the existing 3D simulation technologies has problems such as lack of intuition and accuracy in the context of aerospace tasks. In this paper， an adaptive entity representation method is designed based on the characteristics and requirements of situational representation in aerospace missions. The method dynamically adjusts the representation of entity objects in the 3D scene by analyzing the entity importance level， so as to improve the overall expression ability of the 3D scene， and then improve the multi-expression problem of space entities in aerospace missions.

Key words: space situation, 3D simulation, multiple expressions, visualization, adaptive algorithm