Abstract: The rotary corrosion experiment device was built to study the pre-irradiation effect on corrosion of Be in EDM-1 (No.1 electrical discharge machining oil). With the samples, the mass variations were measured by scales, the microstructure was observed by scanning electron microscope and the composition was analyzed by X-ray photoelectron spectroscopy, respectively. The results indicate that the chemical reaction between the Be and EDM-1 is dominated and corrosive products are generated in the initial experimental stage. Then the mechanical scour becomes the main process in Be corrosion. SO_x and SO₂ are adsorbed chemically on the surface and physically in interior of the corrosive products, respectively. It is revealed that the degree of Be corrosion is serious, reasonable and weak respectively with pre-irradiation only by γ-rays, with pre-irradiation both by neutrons and γ-rays and without pre-irradiation. As a conclusion, the pre-irradiation can promote the corrosion of Be in EDM-1.