Abstract: Objective The purpose was to evaluate fatigue life of TIG welded joints of SMA490BW weathering steel. Methods Three methods, namely blind hole method, X-ray method and finite element analysis, were used to analyze welding residual stress of TIG welded joints of SMA490BW weathering steel, and changes of residual stress caused by cutting small specimens were analyzed. Results The results showed that longitudinal residual stress of SMA490BW weathering steel approached yield strength of material at the peak tensile stress in weld, and rapidly decreased and further transformed into compressive stress away from the center of weld. This distribution pattern was a typical characteristic of longitudinal residual stress distribution. Full size small specimens were cut by wire cutting on the overall test panel for fatigue testing. The peak value of longitudinal residual stress on small specimens was close to 230 MPa, which was about 70% of yield strength. Transverse distribution pattern of longitudinal residual stress remained unchanged. Conclusion Analysis results of this finite element model established in this section were in good agreement with test data, it was confirmed that the heat source model and mechanical boundary conditions of the model were close to actual process. Accuracy and correctness with this calculation model could be guaranteed.