Abstract: High strength and high performance concrete (HSC/HPC) enjoys a wide application. However, the performance degradation and the thermal spalling under high temperature or fire is a bottleneck problem in its applications. Especially, the spalling mechanism is an important issue demanding a thorough study. The study of the explosive spalling mechanism of high strength and high performance concrete under high temperature or fire is reviewed in this paper, with a focus on three kinds of spalling mechanism: the vapor pressure, the thermal stress and the thermal cracking and related influencing factors, the difficulties and challenges. A multi-factor coupling spalling model is established with the steam pressure as the main factor, and the thermal stress and the thermal cracking as the secondary factors, and the high temperature spalling mechanism of HSC/HPC is quantitatively analyzed.