Ablator material for thermal protection system of re-entry capsules and nozzles is often made by carbon/phenolic resin composites.For weight saving, the ablator material are now expected to use as a structural material, however, temperature dependence of mechanical properties were not well understood for system design.In this study, compressive failure mechanism of rayon based carbon fiber satin woven fabric reinforced phenolic resin was investigated after heat treatment with different temperature up to pyrolysis temperature.