Abstract: Structure and performance of the Ti/Al diffusion bonded joint was studied by means of scanning electron microscopy, X-ray diffractometry and shear strength measurement.The results showed that the highest joint strength was 83 MPa.When the bonding temperature reached 525℃, the diffusion reaction occurred, and Al₁₈Ti₂Mg₃ was the unique product from the diffusion reaction. Meanwhile, the joint strength depended on the percentage of solution metallurgical combination area and new phase zone, and it increased with the accretion of solution area but decreased with the accretion of new phase zone.Although interdiffusion of Al and Ti proceeded in the bonding process, Mg did not diffuse to TA2.The results also showed the new phase layer grew in accordance with the linear law.