The thermal stability of sprayable fast-responding Pressure-Sensitive Paint (fast PSP) was investigated to explore the possibility for application in turbomachinery and hypersonic research with temperature above 100 ℃. The first part of the study focused on a widely-used Poly-mer Ceramic PSP (PC-PSP). The effects of thermal degradation on its key sensing properties, including luminescent intensity, pressure sensitivity and response time, were examined for a temper-ature range from 60 to 100 ℃. Severe degradation in intensity and pressure sensitivity was found as temperature reached 70 ℃ or higher, which would cause failure of PSP application in these condi-tions. Subsequently, a fast-responding Mesoporous-Particle PSP (MP-PSP) was developed which did not show degradation effects until 140 ℃. The greatly improved thermal stability of MP-PSP was attributed to: selection of polymer with higher glass transition temperature (polystyrene) to delay the saturation effect of oxygen quenching as temperature increased;porous and hollow struc-ture of particles for luminophore deposition that minimizes polymer-luminophore interaction. This new paint formulation has significantly raised the upper temperature limit of fast PSP and offers more opportunities for applications in harsh environment.