The invention discloses an environmental functional material for emergency control of black water cluster. The material comprises the following components in percentage by mass: 65 to 85 percent of diatomite, modified diatomite, bentonite, modified bentonite, attapulgite, modified attapulgite, kaolin, modified kaolin, modified sepiolite, clay and/or modified clay, 14 to 30 percent of sodium percarbonate and 1 to 5 percent of chitosan. The material has the advantages of convenient use and good treatment effect and can be used independently or matched with other water treatment agents. The produced floccule has a large particle size and dense structure; the settling time is shortened; and the material can effectively improve the indexes such as COD, ammonia nitrogen, phosphorus, chrominance, peculiar smell and the like of a water body. The material is difficult to produce secondary pollution. The required equipment is simple and the operation is convenient, so the material is applicable for the emergency treatment of the black water cluster.