Abstract: Temperature-sensitive paint can be used to measure the temperature field with high spatial resolution. Determination of surface heat flux based on the temperature history measured by TSP is a typical inverse heat conduction problem. The problem can be solved by analytical and numerical solutions based on a one-dimensional double-layer heat conduction model. In engineering applications, the heat conduction model can be simplified to obtain easier calculation methods. The accuracy of heat flux measurement using TSP is affected by the factors including thickness of coating, position of TSP temperature measurement and temperature dependency of thermal properties, which can be improved in paint design, physical modeling and calculation methods, correspondingly. The heat flux measurements using TSP have been successfully carried out in regular hypersonic wind tunnels and shock tunnels. In this paper, two cases were used to discuss the challenges and countermeasures in engineering applications.