Abstract: The thermal stability of γ-Al2O3 at high temperature was studied and simulated industrially in lab, focusing mainly on the influence of the preparation of La2O3 and γ-Al2O3 on the thermal stability of γ-Al2O3. It was found that when using[La (EDTA)]^- as liquid impregnant, keeping properly its concentration can suppress both the reducing specific surface area of γ-Al2O3 and its transform trend towards α-Al2O3 at high temperature, thus improving the thermal stability of γ-Al2O3 to keep its specific surface area bigger. For instance, specific surface area of the samples in which with 1%[La(EDTA)]^- roasted at 1200°C for 10 h is up to 61.34 m²/g. Furthermore, the influence of La2O3 as an additive on the thermal stability was studied and the result showed that such an additive fails to improve the thermal stability of γ-Al2O3.