The effects of pack siliconization on oxidation behaviors of TiAl-based alloy were investigated. Cycle oxidation tests showed that the high temperature oxidation resistance of TiAl-base alloy was greatly improved by pack cementation with 15%Si+85%Al2O3. The specimens before and after cycle oxidation were examined by SEM equipped with EDS. The results showed that the cementation layer is composed of Al2O3 outer layer and a composite inner layer Of Ti5Si3 and an appropriate amount of Al2O3. No spallation or cracking occurred and the weight gain was very small after cycle oxidation at 900degreesC for 238h. The microstructures of composite cementation layer after the oxidation test is similar to that before the oxidation test.