Gas Metal Arc Welding (GMAW) technology, as one of the most popular welding methods is widely used for joining relatively thick sheet steels of body-in-white structures and frames in the ground vehicle industry. It is very flexible for welding various joint geometries with high welding speed. However, fatigue failures most likely to occur at the welded joints subjected to various types of loads due to the inherences of the welded joint, which will result in the degradation of structural and noise performance. So a reliable fatigue life assessment method is needed for vehicle design and analysis engineers to avoid time consuming fatigue tests. Recently, structural stress methods are becoming commonly employed in fatigue life prediction of welded structures due to their less mesh sensitivity compared to conventional stress methods. The structural stresses are usually recovered from the nodal force/moment calculated by finite element analysis (FEA). In this paper, a new nodal force based structural stress recovery procedure is proposed by using weight function to smooth the stresses in elements along the weld line. The equilibrium condition of force/moment and stress continuity is guaranteed in this approach. Mesh-insensitivity is also investigated by comparing the results in various mesh densities and patterns. Published fatigue data of GMAW is utilized to show the effectiveness of this approach in the correlation between structural stress range and experimental fatigue life.