Abstract: Diamond sheets and copper alloy were brazed using Ag-Cu-In-Ti low-melting-point brazing alloy. The wetting behavior of the brazing alloy on the diamond surface was analyzed, and the effects of brazing temperature, holding time, and metal interlayers on the interfacial microstructure and shear strength of the joints were studied. The results indicate that the brazing alloy has good wettability on diamond, and the interfacial reaction product on the diamond side is TiC; the copper alloy and the brazing alloy form a metallurgical bond through interfacial diffusion. Brazing temperature and holding time have a significant effect on the shear strength of the joints. With the increase in brazing temperature or the prolongation of holding time, the thickness of the interfacial reaction layer on the diamond side increases gradually, and the shear strength of the brazed joints increases first and then decreases. Three different metals, Nb, Ni, and W, used as interlayers can all improve the shear strength of the joints. When the Nb metal interlayer is added, the brazing temperature is 760 ℃, and the holding time is 15 min, the maximum shear strength of the brazed joints is 219 MPa.