Most welding element models are simplified rather than detailed to reduce analysis time and to incorporate multiple welding elements into a structure. Nevertheless, a simple model should describe the real process. Using experimental Stress - Strain (S-S) data, we found that the S - S curve of base metals is affected by the strain rate. The force of spot weld was also affected by the strain rate. This indicates that the effect of spot weld should be incorporated into FEM analysis models. The relationship between actual welding and FEM model welding was determined by detailed spot weld FEM analysis. The S - S curve of the base metal was used to determine the failure force of spot weld. As a result of this research, a final spot weld FEM model is proposed. FEM analysis using this new model, as well as an experiment impact test of the hat profile box, was performed. A comparison of FEM analysis results with experimental results demonstrated the utility and accuracy of the new model.