Abstract: Temperature-Sensitive Paint (TSP) is an optical measurement technique for full-field temperature measurement. Via the improvement of the paint response speed and the progress of the heat flux inversion method, TSP shows great potential for applications in the field of hypersonic aerothermal measurements. However, the existing TSP heat flux inversion methods are faced with problems such as the failure of thermal conductivity model and the inaccuracy of coating parameters estimation when applied to the intermittent hypersonic tunnel, resulting in low accuracy of heat flux determination. This paper has proposed a heat flux inversion method based on the one-dimensional double-layer finite base thermal conduction model. The parameters of the coating and base layers are calibrated numerically iteratively using in-situ gauge data, and the TSP temperature histories are further inverted to the heat flux histories according to the in-situ calibration results of parameters. This method can significantly improve the accuracy and robustness of heat flux inversion in fast TSP measurement conducted in the intermittent hypersonic tunnel. In this paper, the effects of the number of iteration parameters, initial iteration values, time range of iteration and coating thickness non-uniformity on the accuracy of heat flux inversion are investigated, and a six-parameter calibration scheme is established. Subsequently, the feasibility and advantages of the proposed method are validated based on the compression corner experimental data obtained in the Mach-6 intermittent hypersonic tunnel. The experimental results show that the TSP heat flux results obtained by the proposed method are in good agreement with the heat flux gauge results, and the deviation of the steady-stage heat flux is less than 0.15 kW/m².