Vacuum diffusion bonding of TiB2 cermet to TiAl-based alloys using Ni interlayer has been carried out at 1123-1323K for 0.6-3.6ks under 80MPa. The effects of joining parameters on the microstructure of the joints and mechanical properties was investigated. The results showed that a TiAlNi2 intermetallic layer and two Ti, Al, Ni solid solution layers were formed at the interface of Ni/TiAl. The shear strength was 110MPa with bonding temperature T=1223K, bonding time t=1.8ks and bonding pressure P=80MPa.