Abstract: Aiming at the cryogenic phase-changed refrigeration mechanism of spatial liquid nitrogen“cold-shield system”under the microgravity and cold background environment in space,the numerical model of flowing refrigeration by cryogenic fluid was established in the cold-shield system of hypersonic vehicle.The flow characteristics of the system under three conditions of super-cooled state,saturated state and overheated state are analyzed and designed.The surface temperature and system pressure and distribution law of cold-shield system in complex environment are studied by numerical simulation.The results show that the surface parameter distribution in high vacuum cold background of the cold-shield system under the saturated,supercooled and superheated inlet conditions can be obtained by numerical simulation.The surface Infrared radiation intensity can be reduced by changing the inlet state parameters of the system to control the system pressure and the surface temperature of the outer wall of the cold-shield system.The saturation state parameter can better meet the requirements of cryogenic strength of systematic materials and infrared radiation intensity.