The work aims to select suitable interlayers to improve the bonding between the three-dimensional connected Cu foams and diamond, thereby preparing three-dimensional connected diamond foams. The three-dimensional connected Cu foams were selected as the template for the preparation of diamond foams. Ti and Cr interlayers were deposited on the surface of Cu foams by magnetron sputtering, and then the diamond films were deposited by hot filament chemical vapor deposition (HFCVD). The morphology, structure and thermal diffusion performance were measured by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman spectroscopy, X-ray diffraction (XRD) and infrared thermal imaging camera. The continuous diamond films are deposited on the Cu foams successfully after coating Cr and Ti interlayers. Under the same CVD deposition paraments, the Cr-modified Cu/Diamond (Cu-Cr/Dia) have larger grain size (5 μm), higher diamond quality and thicker diamond films compared with Ti-modified Cu/Diamond (Cu-Ti/Dia). The interfacial bonding between diamond and copper substrate of Cu-Ti/Dia samples are better than that of Cr-modified samples. And the thermal diffusion properties of Cu-Cr/Dia and Cu-Ti/Dia samples are both better than Cu foam. Cu-Cr/Dia samples have a slightly faster thermal responding than Cu-Ti/Dia samples. The introduction of Cr and Ti interlayers could effectively enhance the interfacial bonding between diamond and Cu foams, thereby the three-dimensional connected diamond foams were prepared successfully, which have potential applications in thermal management, water treatment, electrochemical sensing and other fields.