Residual mechanical property and the corresponding pore structure of high performance concrete(HPC) after being subjected to different high temperatures and cooling regimes were studied and compared with normal concrete(NC).Test results denoted that residual strength of both HPC and NC dropped significantly after exposure to high temperatures.Thermal stress resulted from thermal shock such as rapid cooling was not a predominant factor causing concrete to spall.Porosity in HPC increased much more than that in NC after being exposed to high temperatures.Difference of the cumulative pore volume of the concrete subjected to the different cooling regimes was reduced with increase of temperature.