The long-term goal of prediction of welding distortions in ship sections is to specify an optimal welding procedure to minimize distortions due to welding. The equivalent load method based on inherent strain for material of stainless steel is studied in this paper. A fillet welding experiment followed by infrared thermograph is done. Then simplified elastic plastic analysis model is used while combining the inherent strain theory and the experimental results for accurate and efficient analysis. The results of temperature field in FEM have been supported by the experimental data. Furthermore, the distortions of the stainless steel ship structure are calculated by FE analysis.