The oxidation behaviors of bulk Ti3Si(1-x)AlxC2 prepared by hot pressing were investigated. The results show that the isothermal oxidation behavior of Ti3SiC2 obeys a parabolic law between 900 and 1 100 ℃ and follows a two-step parabolic rate law between 1 200 ℃ and 1 300 ℃. The cyclic oxidation behavior of material is assumed to obey a three-step parabolic rate law at1 100 ℃ and 1 200 ℃. The calculated activation energy of isothermal oxidation is 101.43 kJ/mol. The oxide layers which consist of a mass of α-Al2O3 and little TiO2 and SiO2 are observed on Ti3SiC2 as a dense and adhesive protect scale. The oxidation mechanism varies with the additive aluminum that greatly improves the oxidation resistance of Ti3SiC2.