Aluminum oxide has high thermal and chemical stability, and can be used for high-temperature insulation, making heat shields or protective coatings. The purity of alumina should be very high, and the impurity elements of the material influence the performance of the final product. When analyzing trace elements in alumina, the most important step is the digestion of the sample. Alumina is a material that is difficult to dissolve. The traditional melting decomposition method will bring impurities into the sample. The microwave digestion method is an ideal choice. By virtue of a suitable acid system and temperature and pressure confined space, it can get the ideal decomposition effect in a short time.