The thermal cycling oxidation behaviors of Nb-ion implanted γ-TiAl in air were studied in the temperature range of 1123~1173K. The microstructures of the oxide scales were examined by SEM equipped with EDS. Nb distribution and depth profiles of elements were analyzed by AES. The results indicated that the cyclic oxidation resistance of γ-TiAl alloy could be improved by Nb ion implantation. The reason why Nb-ion implantation improves the cyclic oxidation properties may be ascribed to doping of the titania lattice by Nb5+ ions, which may inhibit the growth of TiO2 and enhance the growth rate of Al2O3. The formation of Al2O3 protective layer at the early stage decreased the oxidation rate and delayed the spallation of oxide scale. But Nb-ion implanted γ-TiAl has no long effect to thermal cycling oxidation resistance.