Abstract: The bonding between chemical vapor deposition (CVD) thick films diamond and cemented carbide was performed by diffusion brazing under controlled temperature, pressure and time. The filled intermediate layer materials are reactive metal Ti foil and Ag-Cu alloy foil.The results show that the diffusion of C and Ti elements occurred on the interface between the diamond and the filled intermediate layer.The rupture occur in the filled material.It can be considered that metallurgical bonding has formed in the interface between diamond-intermediate.