Abstract: The thermal oxidation of beryllium was investigated at different temperatures. The oxidation process, surface state after oxidation, micro-area composition and oxidation thickness were characterized and analyzed by thermogravimetry, AES and SEM. The oxidation behavior and characteristics of beryllium at different temperatures were also discussed. The results show that in the range of room temperature to 400 ℃, the oxidation weight gain of beryllium mainly follows parabolic law, and in the range of 400 ℃ to 900 ℃, the oxidation rate generally obeys linear change. At lower temperatures, the passivation layer formed on the surface of beryllium shows a good protective effect, which is very resistant to corrosion. The oxidation rate of beryllium is highly affected by higher temperatures. Below 600 ℃, the oxidation rate seems to be limited by the diffusion of beryllium atoms towards the surface. Above 800 ℃, oxygen diffuses into the material through the grain boundaries and pores, and oxide films crack during thermal expansion and stress action, which results in serious oxidation corrosion.