Abstract: As the researched objects, TIG welded test specimens of titanium TC4 and TA15 were selected, and their fatigue tests were done under different constant amplitude spectrums with four stress levels, respectively. According to the contrast analysis for the fatigue test results by use of three-parameter-model of fatigue life founded in this paper, the fatigue property of TA15 TIG weld was better than TC4 TIG weld appreciably in 10⁴-10⁶ region.The possible affected factors were discussed.