Abstract: This paper constructs a numerical analysis model for the thermal performance of metallic reflective insulation in the vertical state. Mathematical equations are established based on the theories of energy conservation and heat transfer, and iterative solutions are achieved through a self - developed Matlab program. The trends of experimental data and analytical results are in good agreement, with the maximum error controlled within 7%. The research shows that: 1） Compared with the horizontal state, the heat loss of metallic insulation blocks in the vertical state increases by more than 30%, and it increases with the increase of insulation thickness. 2） The heat loss of the insulation block decreases linearly with the increase of the total number of metal foils. 3） Reducing the emissivity can significantly suppress radiation heat transfer. The heat loss and thermal conductivity decrease linearly as the emissivity decreases. 4） An increase in the hot surface temperature leads to an increase in the average temperature of the air between the foils. The thermal conductivity shows a basically linear growth trend, while the heat loss grows even faster. 5） The temperature difference between metal foil layers increases with the increase of the distance from the hot end, reflecting the significant influence of radiation heat transfer on the temperature gradient. 6） The change of the width of the limited space between metal foil layers is gentle within the range of 5−9 mm, and the convective heat transfer is significantly enhanced beyond this range.This study systematically reveals the quantitative correlation laws between the thermal performance of metallic reflective insulation layers and key design parameters, providing a theoretical basis and optimization strategies for high-precision design and engineering applications.