Abstract: The corrosion and fracture of titanium alloys used in chemical acetic acid plant is analysised in this paper.Experimental results indicate that titanium alloys fracture results from strss corrosion cracking, and in case in a reducing environment lacking oxygen or some side reaction occured to produce some hydrogen pitting and severe general corrosion will happen.and the corrosion problems can not be solved with a thickened titanium oxide layer added on the surface of titanium alloys in this environment.