The work aims to study the effect of W-Mo surface alloying on the high temperature oxidation resistance of γ-TiAl alloy. W-Mo alloying on the surface of γ-TiAl alloy was prepared by double glow plasma surface alloying technology. The oxidation resistance of modified layers was evaluated by isothermal oxidation test. The surface, morphology of cross section and phase composition of oxidation film were anaylized by scanning electron microscope (SEM) and an X-ray diffractometer (XRD). W-Mo modified layer could be prepared on the surface of γ-TiAl by double glow plasma surface alloying technology. The modified layer was 9 μm and the outer layer was 6 μm W-Mo deposition layer. 3 μm diffusion layer was between the deposition layer and the substrate. The W-Mo modified layer was even and dense and the substrate and the modified later had no obvious defects like crack, hole, etc. The content of elements in diffusion layer was distributed in gradient. After isothermal oxidation of 100 h at 750 ℃, the oxidation mass gain of γ-TiAl reached 5.306 mg/cm2 and that of modified layer increased to 2.578 mg/cm2. The mass gain of W-Mo modified layer was only 48.6% of that of γ-TiAl substrate. The modified layer was uniform, dense and free from defects and peeling after oxidation for 10 h, 20 h and 50 h. After oxidation for 100h, the atomic percentage of Mo and W in modified layer decreased to 1:2 from 3:1. The W-Mo modified layer prepared by double glow plasma surface alloying technology can improve the high-temperature oxidation resistance of γ-TiAl alloy at 750 ℃. The oxide film of W-Mo modified layer is continuous and tight after oxidation andcan prevent the diffusion of oxygen. But after oxidation of 100 h, the evaporation of Mo will destroy the integrity of the oxide film and decrease the oxidation resistance.