The effects of lhickness-extensiona1 mode resonance oscillation (TERO) on the catalytic activity for CO oxidation of thin TiO2 and NiO films deposited on a z-cut LiNbO3 (z-LN) single crystal were investigated. TERO at 3 W caused 4-7-fold increases in the catalytic activity of TiO2/z-LN and NiO/z-LN and remarkable decreases in the activation energy of the reaction. Vertical lattice displacement by TERO was decreased remarkably by the presence of the metal oxides. The catalyst activation is due to the interactions of TERO with the carriers in the semiconductor metal oxides.