A Cu-Diamond composite layer was successfully fabricated on CuCr0.5 alloy substrate by electroplating a Cu-diamond composite ‘planting sands’ layer, mould pressing the diamond particles into CuCr0.5 substrate, filling the nano-copper grains suspending in water into the ‘V’ grooves and mould pressing the composite layer to fix the nano-copper powder on Cu-diamond layer and finally sintering the sample with 900℃+60min parameters at Ar+H₂(10vol.%) protecting atmosphere. The surface morphology at different fabricating stages was investigated in details by scanning electron microscopy (SEM) and the surface thermal expansion coefficient of Cu-diamond composite layer was tested by electric resistance strain gauge method. The results show that the ‘V’ grooves were formed at the vicinity of substrate/diamond interface after mould pressing Cu-diamond composite layer fabricated by using W40 diamond powder. The ‘V’ grooves can be perfectly filled by filling the nano-copper grains into the ‘V’ grooves and mould pressing the composite layer and finally sintering the sample with 900℃+60min parameters at Ar+H₂(10vol.%) protecting atmosphere. The surface thermal expansion coefficient of Cu-diamond composite layer was 11.7×10_-6/℃ when the volume percent of W40 diamond particles on Cu-diamond layer was 40~45%.