Abstract: Based on the phase transformation kinetics models for the heat treatment of a metal sheet, the thermo-elastic-plastic constitutive equation was established, which is coupled with the mechanical strain, thermal strain, phase transformation strain and transformation induced plasticity, and suitable for hot-forming of high strength steel. The finite element equations of hot-forming were established based on dynamic explicit algorithm and the constitutive equation accounting for the multi-physical coupling. And the transformation latent heat release of blanks was introduced into the analysis of a temperature field during hot-forming. The KMAS (King Mesh Analysis System) hot-forming module was developed and can be used to predict the thickness, temperature, volume fraction of each phase and the hardness distribution of parts during a hot-forming process. Subsequently, the hot-forming process and final properties of an automotive B-pillar simulated by the KMAS were compared to the experiment. A good agreement between numerical simulation and the experiment results is shown, which confirms the validity of the constitutive equation and the hot-forming module.