Stress distribution and deformation on the cross tension type spot welded lap joint subjected to out of plane tensile load were investigated by finite element method. For the rational design of spot welded joint, it is needed to assess to repeatedly the fatigue life of the joint with various dimensions and welding conditions. In this paper, an automation of repeated process of fatigue life assessment for spot welded cross tension type joint was studied. The process is related to stress analysis in vicinity of weld-toe and fatigue life assessment based on analyzed stress distribution. With the change of design condition including dimensions and welding heat input, the above two works have to be performed. Using the commercial tool for system integration, ModelCenter, an automation of the repeated process for spot welded cross tension type joint based on 2D modeling was achieved. In this automation system, data exchanges between programs regardless of commercial and parametric studies for optimal design can be performed.