Abstract: Multi-layer insulation materials have strong insulation performance in high vacuum environments. With the development of space technology, special requirements have been put forward for the insulation performance of multi-layer insulation materials applied in the liquid hydrogen temperature range, such as higher insulation performance and flame retardancy. A calculation model for the heat flux of multi-layer insulation materials is established based on the layer by layer calculation method. Three commonly used layers of insulation materials, namely 40 layers, 60 layers, and 70 layers, are selected for testing and calculating their heat flux. The effects of layer density, cold and hot boundary conditions on the heat flux of multi-layer insulation materials are analyzed. Finally, the impact of the arrangement of multi-layer insulation materials on insulation performance is analyzed through genetic algorithm, and an optimized arrangement method for insulation materials in the liquid hydrogen temperature range is obtained. This arrangement method can reduce the heat flux by 10.63% compared to the equal density multi-layer insulation material arrangement method.