Ceramic/metal welding connection faces the challenge of poor wetting of sapphire surface by brazing materials. The interface structure of the sapphire/Ag-Cu-3Ti/TC4 alloy brazed joint, the effects of temperature and holding time on the shear properties, and the mechanism of interface connection were studied. The results show that the sapphire side formed a dense metallurgical reaction layer. The microstructure of the reaction layer was composed of Ag base solid solids, Cu base solid solids and the crystal, et al. TC4 alloy side formed a crispy layer and a crystal infiltration area. With the increase in brazing temperature, the shear strength of the brazed joint reduced significantly. As the holding time was prolonged, the shear strength of the brazed joint increased firstly and then decreased. The fracture surface of the brazed joint exhibited a mixed fracture morphology of the sapphire brittle fracture and filler metal "adhesive type" fracture. The brazing connection relied solely on the metallurgical bonding strength between a small portion of Ag-Cu-3Ti brazing metal and the sapphire. During the brazing process, Ti and Cu diffused towards the sapphire side and accumulated on the surface of Al2O3. Sufficient solid-liquid interaction occurred at the interface to form stable intermetallic compounds, and the TC4 alloy side grains continuously grew towards the matrix, resulting in a significant increase in the shear strength of the brazed joint.