Abstract: Diamond/Cu₂Ti and DiamondTi/Cu composites with 60 % volume fraction diamond were manufactured by a pressure infilt ration process. The effects of Ti on the microstructure, interface and properties of diamond/copper composites were comparatively analyzed. The results show that the addition of 0. 1 wt% Ti can greatly improve the interface bonding between copper and diamond. Carbide lamellae can be observed obviously on the interface. By contrast, the interface of Diamond/ Cu₂Ti composites fabricated by adding Ti element in copper to form Cu₂Ti alloy is better than that of Diamond^Ti/Cu composites (Diamond^Ti : Diamond coated with Ti). The thermal conductivity of Diamond/Cu₂Ti composites is 621 W(m·K)^-1 and that of Diamond^Ti/Cu composites is 403. 5 W(m·K)^-1, both of which are higher than the thermal conductivity of Diamond/Cu composites.