The issue of thermal management in electronic packaging is one of the important technical bottlenecks hindering the development of integrated circuits. Diamond/copper composites have excellent performance in the field of thermal management, but the difficulty in their complex structure formation leads to very limited applications in the field of water cooling in electronic packaging. In this research, we aimed to enhance the sintering performance between the green body and the composite plate by employing a silver doping strategy, thereby addressing the thermal management challenges in electronic packaging. We fabricated composite base plates and pin-fin type composite base plates and evaluated their application benefits in both indirect and direct water cooling scenarios. Our findings demonstrate that the silver-doped copper billet achieve good sintering performance when combined with tungsten-coated diamond/copper composite plates. The composite base plate and the pin-fin type composite base plate effectively reduce the temperature of the heating sheet by 5-6°C and 4-5°C during water-cooling tests respectively. The numerical simulation results were in good agreement with the experimental data, confirming the excellent thermal uniformity of the composite structures. This research successfully overcame the limitations associated with the low thermal conductivity of traditional packaging components and the challenges in fabricating complex structures using diamond/copper composite materials.