The loads for bolster fatigue strength analysis were determined based on the load bearing characteristic. The structural stress distribution under each load case was obtained and the stress component to the weld coordinate system were calculated. According to the standard DVS 1612, the bolster fatigue strength was estimated on the basis of the degree of utilization for each stress component and the composition value. The results showed that the stress transverse to the weld has a major effect on the bolster fatigue strength and there is slight influence of the other stress component on it. Structure strength test verified the effectiveness of the antifatigue technology.