Abstract: Diamond/copper composites are considered promising materials for next-generation thermal management applications due to their exceptional thermal conductivity and adjustable coefficient of thermal expansion, which address the growing heat dissipation requirements of electronic devices. However, the poor wettability between diamond and copper results in weak interfacial bonding, leading to the formation of significant voids within the composite. These voids contribute to high interfacial thermal resistance, which in turn compromises the overall thermal performance. To overcome these challenges, current research primarily focuses on improving sintering techniques and modifying the interfaces to enhance both interfacial bonding and thermal properties. This paper reviews the common preparation methods for diamond/copper composites, highlighting two main strategies for interface modification: metallization of the diamond surface and alloying of the copper matrix. Both approaches introduce elements at the diamond-copper interface, leading to the formation of carbide layers that strengthen the interfacial bonding and improve thermal conductivity. Elements such as W, Mo, Cr, Ti, Zr, and B are frequently employed in these modifications, as they effectively enhance the interface, potentially increasing the composite's thermal conductivity to over 900 Wm?1K?1. The paper also explores the role of first-principles calculations in diamond/copper composites, which provide valuable insights into the mechanisms of interface improvement and enable the prediction of how different modifying elements affect the composite properties. These theoretical studies can offer guidance for experimental design, potentially reducing research costs. Finally, the paper concludes by discussing future research directions for diamond/copper composites, emphasizing both preparation techniques and interface modification strategies.