It is well known that the fatigue strength of weld toe can be improved by peening which introduces the compressive stress. However, when the compressive over load (OL) is subjected after peening, the compressive stress of welded toe is released and effect of improvement of fatigue strength becomes small. In the previous research, the authors carried out fatigue tests of out-of-plane gusset joint and clarified that the improved fatigue strength is reduced by subjected the compressive OL. In this paper, to evaluate the reduction of improved fatigue strength by the compressive OL, fatigue tests of T-joint were carried out. Furthermore, fatigue strengths of out-of-plane gusset joint and T-joint subjected compression OL after peening were estimated by using the elasto-plastic large deformation analysis and the modified Goodman Diagrams.