Abstract: With the rapid development of new energy, electronic packaging and high-end equipment manufacturing industries, the demand for high-purity and low-cost alumina raw materials keeps rising, thus improving alumina production efficiency and reducing energy consumption and impurity content has become an important direction for the technological upgrading of the alumina industry at present. The main industrial production methods of alumina include the Bayer process, sintering process and combined process, among which the Bayer process has become the mainstream route for global alumina production due to its mature technology, low energy consumption and high product purity. In this study, bauxite from a plant in Shanxi Province was used as raw material to carry out a comparative study on the lime Bayer process digestion test of ores with different MgO contents in bauxite, the MgO content and digestion rate in bauxite were mainly analyzed to explore the effect of MgO content on the digestion rate of the lime Bayer process. The results show that the digestion rate shows an obvious linear downward trend with the increase of MgO content.