Ti-66Ni (wt.%)+B composite brazing alloy was used to braze Ti₂AlNb alloy. The interfacial microstructure and forming mechanism of the brazed joints were studied. The effect of brazing temperature and B content on the interfacial microstructure and mechanical properties were investigated. The results showed that the typical microstructure of the joint was: Ti₂AlNb/B2/B2+Nb₃Al+τ₃+TiB/τ₃+Ti₂Ni/B2+Nb₃Al