Abstract: Eutrophication of rivers and lakes is one of the disastrous problems in the world, which can resultin frequent occurrence of cyanobacteria and coastal red tide. Clay, as one of the technical approaches to solve this environmental problem, has achieved some successes in the emergency treatment for algal bloom and red tide. Due to naturaldefects of clay algae, some experts carried out much study on the types and content of clay and its treatment performance for algae, including organic and inorganic modification, clay algae performance, screening and integration of clay with excellent property, and the treatment method for algae and eutrophication. Breakthrough has been achieved especially in solving the problems of algae and eutrophication, and in emergency and long-term comprehensive management. This studydemonstrates that clay has broad prospects for its unitilizaiton.