Abstract: The present study took the drying process of porous thermal insulation material for dew-point temperature of -50℃ as the object. The simulation analysis and experimental verification were carried out for its moisture migration characteristics under convective drying conditions.The quantitative effects of inlet pressure, inlet temperature, wind channel width and insulation layer aspect ratio on the drying process were obtained.The results show that the extended Darcy's Law can effectively reflect the water vapor migration process in porous thermal insulation materials. Increasing the inlet pressure can improve the water transfer efficiency and accelerate the drying process.The effect of inlet temperature on the results is not obvious, and its effect is reflected in the effect of buoyancy. For specific porous insulation materials, there is a critical aspect ratio, above which the wind channel will increase the overall drying time. Below this critical value, the wind channel reduces the overall drying time.For pearlite with porosity of 70.8%, the critical aspect ratio is 0.09.