Fabrication by welding may result in stress concentration regions in the joints and it may be caused by weld imperfections or geomatrical discontinuities. Thus, fatigue strength of welded details was essential for fatigue design of bridge components. In this study, constant amplitude fatigue tests on load-carrying, nonload-carrying fillet welded specimen and transverse groove welded specimen were carried out, and fatigue strength were evaluated. The effects of curvature radius $ ho$ and tangential angle $ heta$ of fillet welded toe were also investigated. From the result of this study, fatigue strength of nonload-carrying fillet welded specimen was higher than that of load-carrying specimen, and smoothing weld surface in the transverse groove welded specimen improved fatigue strength. The smaller $ ho$ and $ heta$, the higher probability of fatigue crack occurance. Thus, the effect of weld toe shape was play a role in fatigue strength and fatigue crack initiation.