Systems of Pd supported on various La2O3-modified gamma-Al2O3 and CeO2-Al2O3 catalysts were tested for catalytic methanol decomposition and characterized by means of XRD, BET, TPR, H-2-chemisorption and CO-FTIR. The addition of lanthanum significantly improved the selectivity of CO and H-2 for all the catalysts but showed a different influence on the catalytic activity in two systems. Methanol conversion decreased on La2O3-modified Pd/gamma-Al2O3 catalysts, in line with the reduction of Pd dispersion, while the addition of La2O3 improved the dispersion of Pd and reinforced Pd-CeO2 interaction for La2O3-modified Pd/CeO2-Al2O3 catalysts, which resulted in a high production rate of CO and H-2. Thus, a synergistic effect between CeO2 and La2O3 was observed on gamma-Al2O3-supported Pd catalyst for methanol decomposition.