The adsorption and dissociation of H2O2 on the surface of CuO and Ag/CuO have been investigated using density functional theory (DFT). The most stable structure of the small molecules decomposed from H2O2 adsorbed on the surface of CuO and Ag/CuO was determined. The results showed the adsorption energy of H, O, OH, OOH on Ag-doped CuO surface was greater than pure CuO surface. Furthermore, the effect of Ag-doped CuO surface on the decomposition of H2O2 was investigated. We found that the decomposition paths of H2O2 on CuO and Ag/CuO were all through H2O2 -> 2OH -> H2O + O, but the decomposition of H2O2 on the Ag/CuO surface was achieved easier than on the pure CuO surface. The above data indicated that doping of Ag can indeed make the decomposition of H2O2 on the surface of CuO easier. The present work provides theoretical guidance for improving CuO adsorption capacity in the future.