In this paper, a 2D axisymmetric model of thermo-elastic–plastic finite element method (FEM) is developed to analyze the mechanical behavior of resistance spot welding (RSW) process using commercial software ANSYS. A transient temperature field obtained from a prior performed thermal–electrical simulation of RSW process is applied as nodal load on the model. The temperature-dependent properties and plastic behavior of materials are taken into account during the simulation. The distributions and changes of the contact pressure at both the faying surface and the electrode–workpiece interface are obtained through the analysis. The stress and strain distributions in the weldment and their changes during the RSW process are determined. The deformation of the weldment and the electrode displacement are also calculated.