A series of single and mixed oxides of CuO-MoO3 system were prepared by thermal treatment of pure and mixed basic copper carbonate and ammonium molybdate tetrahydrate solids. The thermal behavior of the pure and binary salts has been studied using thermal analysis (TG-DTA) technique. The thermal products were characterized using the X-ray diffraction analysis. The results revealed that, pure solids decomposed to CuO, MoO3 and Cu2O phases at 250, 340 and 1000oC respectively. Solid-solid interaction takes place between single oxides forming different phases of copper molybdate depending on treatment temperature and mixture composition. The degree of crystallinity of the detected phases was affected by calcination temperature of solids and composition. The catalytic activity of single and binary oxides was tested in decomposition of hydrogen peroxide as a model reaction. The catalytic activity of mixed oxides was found to be higher than that of single oxides at different treatment temperature. The mechanism of decomposition reaction over the prepared oxides was discussed.