Cu2O thin film is prepared using the electrodeposition approach. XRD, XPS, SEM, PL and UV-vis are used to characterize the thin film microstructure, morphology and optical properties. Response surface methodology is employed to optimize the main influences of photocatalytic degradation, the quadratic multinomial mathematical model is also established. Photocatalytic degradation process of methylene blue is studied as well. The results indicate that the prepared Cu2O thin film is of high-purity with the preferential orientation of (1 1 1). R-2 is 0.9888 in the established quadratic model, which is of better fitness and higher significance. The optimal degradation conditions are obtained. Under this condition, degradation rate of methylene blue can reach over 98.2% in 3 h. The methylene blue molecules can be decomposed completely. Recycling results reveal that more than 94.2% of methylene blue can be decomposed within 7 cycles, which could still reach 81.8% after 11 cycles. (C) 2015 Elsevier Ltd. All rights reserved.