Abstract: Butt and cruciform welding joints of titanium alloy were treated with ultrasonic peening and the property of the joints before and after the ultrasonic peening was investigated.The test results manifested that the welding residual stress of the joints reduced remarkably and the fatigue strength and fatigue life of the joints were improved.For the butt and cruciform joints of Ti80 alloy,the fatigue strength increased by 22.7% and 64.5% separately and the fatigue life increased by 5.4 and 13.5 times separately.For the butt joints of TA2 and Ti75 alloy,the welding residual stress decreased by 68% and 65% separately.