Abstract: Vacuum brazing of Ti₂AlNb alloy was successfully achieved using a newly designed Ti₃₅Zr₃₀Nb₁₅Cu₁₀Ni₅Co₅ amorphous filler metal, and the effect of brazing temperature on the microstructure, mechanical properties, and fracture behavior of the joints was systematically investigated. The results showed that the filler metal exhibited sound wettability on the Ti₂AlNb substrate, producing joints with continuous and sound interfaces. The brazed joint mainly consisted of a diffusion reaction zone adjacent to the base metal and a central reaction zone within the brazed seam. As the brazing temperature increased from 960 to 1060 °C, the joint microstructure evolved from the coexistence of the β/B2 phase and the (Ti, Zr)₂(Ni, Cu, Co) phase, to a β/B2-dominated structure containing a small amount of residual (Ti, Zr)₂(Ni, Cu, Co) phase, and finally to the coexistence of the β/B2 phase and the (Ti, Zr)(Al, Ni, Cu) phase. The shear strength of the joints first increased and then decreased with increasing brazing temperature, reaching a maximum value of 391.23 MPa at 1010 °C for 30 min. Fracture analysis revealed that the joint exhibited quasi-cleavage transgranular brittle fracture at 960 °C, mixed brittle-ductile fracture at 1010 °C, and fully transgranular cleavage fracture at 1060 °C. An appropriate brazing temperature promoted interdiffusion of interfacial elements, suppressed the excessive formation of brittle reaction phases, and improved microstructural uniformity, thereby enhancing the mechanical performance of Ti₂AlNb brazed joints. These findings provided theoretical guidance and technical support for the development of novel filler metals and the optimization of brazing processes for Ti₂AlNb alloy.