With the wide and increasing applications of concrete, especially the high performance concrete (HPC), it is of critical importance in science and economy to establish a mathematical model to simulate the coupled, multiphysical-chemical processes, which occur and develop in concrete. Concrete is modeled as a deforming porous medium unsaturated with multiphase pore fluids, based on mass, momentum and energy conservation equations for the multiphase system and existing work published in literatures, the coupled thermo-hygro-mechanical behaviors occurring in concrete at high temperature (below the critical point of water 647.3K) are numerically simulated by means of the finite element method, the mechanisms of the complex procedures are analyzed, which is the basis of further proving numerical model of the coupled multiphase for concrete at high temperature, fireproofing and disaster reduction.