Abstract: Addressing the current issues of insufficient thermal conductivity and low heat dissipation efficiency in electronic packaging materials. In this paper, copper-diamond composites were prepared using three processes, namely, traditional powder metallurgy (PM), stirring friction processing (FSP) and spark plasma sintering (SPS), and their microstructures, densities, interfacial states, and thermal conductivities were comparatively analyzed. The results show that the copper-diamond composites with 50 vol.% diamond was prepared by SPS at a sintering pressure of 30MPa and a holding temperature of 900℃ for 20min, which have the best performance with diamond particles uniformly distributed on the copper matrix. The densification, thermal conductivity and coefficient of thermal expansion of composite is 97.4%, 517.04W-m-1-K-1and 6.63×10-6k-1, respectively. The composite material interface contains a transition layer of less than 1 micron, with good bonding quality. The performances of composites of traditional powder metallurgy preparation was second; that of friction stirring processing was the worst.