The invention provides a high temperature resistant titanium-aluminium base alloy and a method for preparing the same, wherein, the alloy which belongs to gamma-TiAl alloy has components of Al of 44.0-48.0at%, Nb of 3.0-5.0at%, Cr of 0.2-2.0at%, Ni of 0.1-0.8at%, Si of 0-0.8at% and the rest are Ti and ineluctable impurity elements; the method comprises steps of using titanium sponge, AlNb alloy, AlCr alloy, Ni, Al and Si as the raw material, smelting, casting and shaping the raw material in a vacuum consumable electrode electrical arc skull crucible or a vacuum induction furnace, and when the casting process is performed, Ti-Al alloy casting ingot can be casted after vacuum melting or be casted after argon-filling smelting.The alloy of the invention has characteristics of favorable room-temperature plasticity, creep-resistance capability and anti-oxygenic property, can be used under a temperature of 800-900 DEG C, is suitable for the casting of parts with thin walls, can improve the use characteristics of aircraft engines and car engines, and has a wide market outlook.