Diamond/Cu composites have advantages of low density, high thermal conductivity and tailorable coefficient of thermal expansion (CTE), and possess a good thermal matching performance with new generation chips. Therefore, it has a widespread application prospect in electronic packaging with high heat flux density and other fields. However, due to the poor wettability between diamond and Cu as well as high interfacial thermal resistance, bringing about the conductivity of composite is even lower than copper, which restricts its application. The interface of composite is modified to transform their mechanical and physical bonding state into a chemical and metallurgical bonding by pre-metallization, pre-alloying copper matrix and optimization of composite processing so as to improve wettability at home and abroad nowadays. In this paper, surface modification, interface theory related to thermal conducting model and research development in finite element simulation are reviewed. The difficulties of fabricated process, thermal conducting models, and key direction of future development are discussed. The effects of parameters such as diamond content and particle size on microstructure and thermal conducting performance are summarized.