Abstract: Estimation of surface heat flux by using interior temperature is a type inverse heat conduction problem. This paper presented the surface heat flux estimated from thermocouple measurements of the first flight of CARDC space vehicle model by one dimensional surface heat flux estimation method. By comparing with numerical prediction, the result was used to detect the boundary transition region, achieved the desired goal. But one dimensional method is relatively simple and has its limitations. For example, it cannot simulate the local three-dimensional heat transfer between the sensor and nearing vehicle structure, and a small part of unreasonable neglect heat flux was found in the small part of the estimation results as the most part was in good agreement with numerical prediction. In order to overcome this defect and improve the accuracy of estimation, surface heat flux estimation method for the three-dimensional heat transfer model was used to analyze thermocouple measurements, and the result of three-dimensional model was more reasonable than that of one dimensional model. The influences of thermal contact resistance and surface temperature of sensor were also considered in the three-dimensional model. Generally speaking, the heat transfer of temperature measurement units is very complicated, and the heat flux estimation based on precise heat transfer model can effectively obtain high-precision surface heat flux which can be used to support the study of aerodynamic heating. The estimation results also indicate that the heat flux estimation method used in this paper has great application potential in flight test.