Monoclinic nanostructured CuO films with star-like morphology on indium tin oxide (ITO)-coated glass substrates were successfully synthesized by electrodeposition method in acidic solution with the pH of 5.7. The as-synthesized films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis. The influence of different electrodeposition parameters and annealing temperature on the growth of CuO films were investigated. The results showed that the nanostructured CuO film was well-crystallized and electrodeposition voltage is the main factor to control its morphology. Moreover, good photocatalytic activity was exhibited and photo-degradation rate to methylene blue can reach 95%. Its optical energy band gap is 3.3 eV. The plausible growth mechanism for the formation of CuO film with star-like structure is also proposed for the first time. (C) 2014 Elsevier B.V. All rights reserved.