Abstract: TC4 titanium alloy compression bar passed the static tensile test,but it was broken during the assembling. The fracture characteristics of the compression bar were analyzed by scanning electron microscope（ SEM）, and the metallographic structure near the fracture was analyzed by metallographic microscope,and the hydrogen and oxygen contents were measured by energy dispersive spectrometer（ EDS）. Brittle fracture characteristics in the source area of the fracture was observed. The energy spectrum analysis of the fracture surface showed that hydrogen element exceeded the standard.The metallographic structure near the fracture showed Weissenite structure existed in the area,and the basketweave structure was also found. The results show that the fracture of the compression bar is brittle fracture. In the forging process,the deformation of the compression bar is not sufficient,which caused the forming of the Weissenite structure and the basketweave structure. This metallographic structure state is easy to make oxygen and hydrogen more easily diffuse along theα and β grain boundary,which will reduce the material plasticity,and increase the brittleness of the titanium alloy compression bar,and finally lead to the brittle fracture of the titanium alloy compression bar.