Abstract: Scenedesmus obliquus (Turp.) Kutz. has fairly high ability to absorb radioactive materials. The total amount of absorption is proportional to the duration of the experimental period.The absorbing ability of Scenedesmus obliquus has certain relation with the illuminating time the algae received. The longer illumination they receive, the higher absorbing ability they exhibit.Pretreating separately with y-ray, infrared rays or supersonic waves promotes the ability for absorbing radioactive materials of Scenedesmus obliquus.In view of its ability of absorbing and accumulating radioactive materials, it is possible to use this alga for cleaning the water body polluted by such wastes.