The membrane structure roof is widely used in large-span buildings such as stadiums and gymnasiums because of its full use of natural light sources and flexible forms. In order to solve the prominent problems such as poor thermal insulation performance and prone to external environmental factors, the multi-layer membrane structure design, laying of insulation layers, and other schemes are applied to engineering practice. However, there is still a gap in the relevant research of thermal environment monitoring and analysis. In order to study the thermal environment of the double-layer PTFE (polytetrafluoroethylene)-aerogel roof, multi-point thermometers were uniformly arranged to monitor, and the overall temperature field was constructed using the measured data. A thermophysical model which could accurately reflect the change of temperature field was established, whose average error was less than 5%. With the laying of roof insulation layer as the variable, three working conditions, i.e., no insulation layer, only rock wool insulation layer, and all aerogel insulation layer were constructed based on the model. The comparison indicates that the laying of aerogel reduces the average temperature of indoor space by 2.0 ℃, the original working condition has the best thermal insulation effect, and the average temperature difference between indoor and outdoor is 9.6 ℃. This paper can provide reference for the thermal insulation design of membrane structure roofs.