We investigated the morphology of CuO powders synthesized by three processes: homogeneous precipitation, homogeneous precipitation under microwave irradiation, and heat treatment of precursor at 600°C. Homogeneous precipitation process was applied to a mixed aqueous solution of copper precursor complex, which was obtained from cupper nitrate and hexamethylenetetramine. The 2.45 GHz microwave irradiation to a precursor solution induced the formation of CuO powders with special morphology at 95°C in aqueous solution. Also the rapid formation of CuO from precursor by microwave was revealed in comparison with the processes without microwave irradiation.