The TC4 alloy was brazed to SiO2 composite using AgCu-4.5Ti filler alloy. The interfacial microstructure of joint was analysed and its formation mechanism was discussed. The influence of brazing temperature on the interfacial microstructure and the shear strength of joints was studied. The typical interfacial microstructure was SiO2 composite/TiSi2/Cu4Ti3+Cu3Ti3O/Ag(s, s)+Cu(s, s)/TiCu/Ti2Cu/α, β-Ti/TC4 alloy at brazing temperature 850 ℃, for 10 min. The increase of brazing temperature would increase the thickness of interfacial reaction layers near SiO2 composite and TC4 alloy, and the AgCu eutectic microstructure would disappear at 870 °C. The shear strength of joint also changes with the increase of temperature. The shear strength of the joints reaches a maximum of 7.8 MPa when the temperature is 850 °C and the holding time 10 min