Abstract: With the continuous advancement of technologies such as 5G, optical modules, and semiconductors, effective thermal management materials have become crucial. Diamond exhibits high thermal conductivity and a low coefficient of thermal expansion; however, its high hardness and brittleness limit its standalone application. A metallic matrix can provide structural support, thereby facilitating packaging applications. Consequently, diamond/metal matrix (Al, Cu, Ag) composites are considered among the most promising thermal management materials. This paper reviews the current research status of diamond/metal matrix composites both domestically and internationally, focusing on the preparation and thermophysical properties of diamond/aluminum, diamond/copper, and diamond/silver composites. The discrepancy between experimental and theoretical thermal conductivity values is also discussed. Subsequently, existing issues concerning interfacial bonding and interfacial thermal resistance, along with improvement strategies such as diamond surface modification, matrix alloying, construction of diamond network structures, and diamond double-layer coating, are elaborated. Furthermore, the challenges associated with laser powder bed fusion of diamond/metal matrix composites, particularly diamond graphitization, are analyzed, and corresponding strategies are discussed. Finally, a summary and outlook on the development of diamond/metal matrix composites for thermal management applications are provided.