NOVELTY - Water purification system using ecological wetland island to purify water by collecting the precipitated sludge of underwater floor, and sequentially filtering aquatic plants, and microorganism using a filter, is claimed. The ecological wetland island is located on detention pond or dam. The precipitated sludge is collected by a collecting tank (10) which is vertically mounted with a supply pipe in a rectangular box (50) emerged on surface of the water, connected to an air supply pipe on one side of the supply pipe, located on underwater floor and lower end of the air supply pipe.    USE - Used as water purification system.    ADVANTAGE - The system is convenient to maintain, and economical.    DETAILED DESCRIPTION - Water purification system using ecological wetland island to purify water by collecting the precipitated sludge of underwater floor, and sequentially filtering aquatic plants, and microorganism using a filter, is claimed. The ecological wetland island is located on detention pond or dam. The precipitated sludge is collected by a collecting tank (10) which is vertically mounted with a supply pipe in a rectangular box (50) emerged on surface of the water, connected to an air supply pipe on one side of the supply pipe, located on underwater floor and lower end of the air supply pipe, provided with a board having multiple holes and located on upper surface of the box. The board is inclined at lower side. The aquatic plants purification is carried out in an aquatic plants tank (20) planted with an aquatic plant, filled with a rooting radical cannonade of cocoa fiber or natural non-woven fabric within the box. The microorganism purification is carried out in an artificial aquatic plant tank (30) provided with a microorganism tank on floor of the box, provided with Bacillus subtilis culture liquid. The upper surface of the microorganism tank is provided with multiple holes. The artificial aquatic plant is made of synthetic resin tube having a small hole or fibrous tissue in the holes. The filtration is carried out using an ion filter tank (40) sequentially laminated with gravel, sand, charcoal, and porous fibrous tissue.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the water purification system.    Collecting tank (10)    Aquatic plant tank (20)    Artificial aquatic plant tank (30)    Ion filter tank (40)    Box (50)