Layered Ti-clad diamond/Cu composites used in electronic packaging were prepared by spark plasma sintering (SPS) and hot pressing (HP), respectively. The structure was determined by Scanning Electron Microscopy (SEM) and the thermal properties, including the thermal conductivity (TC) and the coefficient of thermal expansion (CTE) were analyzed. The theoretical TC of the layered composites (446.66 W.m_-1K_-1) was calculated by the modified Hasselman and Johnson (HJ) model considering the influence of the TiC interface and the CTE was determined by dilatometer. The results show that the sample of SPS has fewer defects than that of HP and the interfacial bonding affects the TC of the composites significantly. A schematic graph of the interface influences is proposed and the TC decreases with the increasing thickness of carbide layer and air pores. In this regard, the composites with a thin carbide layer and no air pores should be processed to achieve a high TC.