Abstract: According to the requirements of Beijing Spectrometer Ⅲ (BESⅢ) beam pipe, the physical properties of several materials were compared and powder metallurgy beryllium was chosen as the material for the central pipe of the BESⅢ beam pipe. Weight-loss method was used to study the corrosion of powder metallurgy beryllium in No.1 oil for electron discharge machining (EDM-1). The result shows that the anticorrosive property of powder metallurgy beryllium in EDM-¹ is high. The corrosion rate, 4.18×10^-7 kg•m^-2•h^－1 in initial stage, becomes small with the lapse of the time and stabilizes at 1.54×10^-7 kg•m^-2•h^－1 at last. It can be estimated that the powder metallurgy beryllium will be corroded 19.9 μm in the depth in 10 years and it accounts for 3.32% of the smallest thickness of the central pipe, which satisfies the requirements of the BESⅢ.