Vacuum diffusion bonding of TiB2 cermet to TiAl -based alloys using Ni interlayer has been carried out at 1123~1323 K for0.6~3.6 ks under 80 MPa. The effects of joining parameters on the microstructure of the joints and mechanical propertieswas investigated. The results showed that a TiAlNi2 intermetallic layer and two Ti, Al, Ni solid solution layers were formed atthe interface of Ni/TiAl. The shear strength was 110 MPa with bonding temperature at 1223 K, bonding time for 1.8 ks andbonding pressure under 80 MPa.