Abstract: In this paper, the effect of fluorine ion implantation and NH₄F solution treatment on the oxide layer structure of TiAl alloy after high temperature oxidation is studied. The results show that the process parameters have a great effect on the structure and density of the oxidation layer. The alloy with fluorinated treatment enjoys better high temperature oxidation resistance than that without the treatment. The increase of surface fluorine content will lead to an increase of Ti content and a decrease of density of the oxidation layer.