Heat flux measurement data are indispensable in the design of a heat protection system for the atmospheric re-entry of a spacecraft. One of the instrumentation techniques used to obtain heat flux data is Temperature-Sensitive Paint (TSP). Shock tubes and shock tunnel are used to simulate re-entry, but the duration of a shock tunnel test is extremely short. In order to apply TSP to high speed phenomena, a new TSP with a large luminescence and high responsivity was developed. In a luminescence test, the luminescent intensity peaked when the mixing ratio was set at 50%, and the intensity was about twice the original one. In a response time evaluation test, the response time was improved by increasing the mixing ratio. When the calcium silicate mixing ratio was set at 50%, the improved TSP achieved a response with a time constant of 0.205ms. We applied this TSP to a high-enthalpy wind tunnel and could obtain the heat flux data. Nomenclature q = heat flux, W m -2 q norm = normalized with a maximum heat flux c = specific heat, J kg -1 K -1 I = luminescent intensity t = time, ms a = thermal diffusivity, m 2 s -1 k = thermal conductivity, J s -1 m -1 K -1 ρ = density, kg m -3 L = film thickness, m A n = calibration coefficient T = temperature, K τ = time constant, ms θ = temperature change from initial temperature, K W = error function subscript: ref = reference condition max = maximum value b = base p = polymer 1 Master's course student,