A series of Ce1-xCuxO2 nanocomposite catalysts with various copper contents were synthesized by a simple hydrothermal method at low temperature without any surfactants, using mixed solutions of Cu(II) and Ce(III) nitrates as metal sources. These bimetal oxide nanocomposites were characterized by means of XRD, TEM, HRTEM, EDS, N-2 adsorption, H-2-TPR and XPS. The influence of Cu loading (5-25 mol%) and calcination temperature on the surface area, particle size and catalytic behavior of the nanocomposites have been discussed. The catalytic activity of Ce1-xCuxO2 nanocomposites was investigated using the test of CO oxidation reaction. The optimized performance was achieved for the Ce0.80Cu0.20O2 nanocomposite catalyst, which exhibited superior reaction rate of 11.2 x 10(-4) mmol g(-1) s(-1) and high turnover frequency of 7.53 x 10(-2) s(-1) (1% CO balanced with air at a rate of 40 mL min(-1), at 90 degrees C). No obvious deactivation was observed after six times of catalytic reactions for Ce0.80Cu0.20O2 nanocomposite catalyst. (C) 2011 Elsevier B. V. All rights reserved.