The effects of brazing temperature, holding time and joint clearance on the interface reaction during of titanium vacuumbrazing have been studied. The results show that the interdiffusion takes place between the filler metal and the base titanium duringthe brazing process; the base titanium dissolves into the molten braze alloy and the filler metal in to the base titanium. A nickel-richdiffusion zone is formd between the base titanium and the brazing solder. In it the nickel exists in the form of a Ti2Ni compound, andalso trends to penetrate into the titanium grain boundary.