TiAl alloy powder was prepared by high-energy ball milling and heat preservation under the condition of low temperature and high vacuum with titanium powder of 43 μm and aluminium powder of 9~12 μm as starting materials. After heat treated for different time and at different temperatures, the alloying of blended powder of titanium and aluminium was investigated. The results show that the alloy powder with the main intermetallic compounds of TiAl and a small quantity of Ti3Al can be obtained through 1 h high-energy ball milling and heat preservation at 500 oC for 2 h, and 600 oC for 3 h in high vacuum. The particle size of the prepared alloy powder is about 20 μm.