Abstract: The T-joint was subjected to ultrasonic impact treatment using ABAQUS software, and the results were imported into the implicit analysis module to obtain a stable residual stsress field. Then different tensile loads were applied to the joints after impact treatment to calculate the ASME structural stress under different mesh sizes, and the mesh insensitivity of the method was verified. Comparing the stress concentration factor of AMSE structural stress and ⅡW structural stress of welded joints with and without ultrasonic impact treatment, it is found that the stress concentration factor at weld toes could be effectively reduced by ultrasonic impact treatment, but the ASME structural stress method was more sensitive to load changes. Based on the master S-N curve and the ⅡW structural stress S-N design curve, the fatigue life of ASME structural stress method and ⅡW structural stress method were given. The results shown that the fatigue life predicted by ASME structural stress method tended to be relatively conservative.