TiAl alloys, which are characterized with low density, high strength, high hardness, high creep strength at evaluated temperature, high temperature oxidation resistance, high resistance to corrosion, are normally chosen as the preferred material for the heat-resistant structure of aerospace, aviation and automobile engines. By calculating the box-counting dimension and lacunarity of micro-structure of TiAl alloys, a quantitative analysis of the fractal characteristics of Ti-46.5Al (at.%) alloys has been made after three different kinds of heat treatment, followed by a further analysis of their effects on corrosion resistance. The results show that the fractal box dimension basically reflects the complexity of micro-structure of TiAl alloys in different states, the fractal structure of micro-structure of 2 h TiAl alloys, which are sintered at 1 300 ℃, being the simplest and the best corrosion resistance performance, and with the annealing of 12 h at 1 040 ℃ being the most complicated. The result of lacunarity analysis indicates that cast TiAl alloy presents the most complex anisotropy micro-structures, which leads to the poorest corrosion resistance among three types of TiAl alloys.