Thermal performance evolution test of the key material polyurethane board and vacuum insulation board under multi field coupling was carried out for two typical climatic zones: hot summer with warm winter and hot summer with cold winter. The aging mechanism of key materials was investigated and the thermal insulation performance of the roofing system parts was improved through COMSOL simulation. Through experiments, it is found that the effect of freeze thaw cycling on the adiabatic performance of polyurethane materials is greater than that of heat and humidity aging in hot summer and winter cold climates; the large part solution is the best splicing form in the roof insulation system; the optimized heat transfer of polyurethane board and vacuum insulation panels reduces the heat transfer coefficient of the part to 0137W/(m2·K), the key heat transfer coefficient of the parts is reduced to 0065W/(m2·K).