Nano-Al2O3 is a promising reinforcing material of Cu based nano-composites due to its unique mechanical properties. However, the wetting property of Cu matrix and nano-Al2O3 is poor. The wetting property and the interfacial strength between nano-Al2O3 and Cu matrix would be improved through electroless plating a Cu film on nano-Al2O3 powders. Effects of key factors of complexing agent and reducing agent in bath, bath temperature and bath operating condition on the electroless plating process as well as the quality of the Cu film were studied by SEM, TEM, XRD and EDS. The plating process was then optimized, and the Cu coated nano-Al2O3 composite powders with uniform size and good dispersion were finally obtained. All these work will construct a steady base for the fabrication of A12O3/Cu nano-composites.