The Anyang stream is one of the Han River in Seoul Metropolitan area. It is 35.1㎞ long, has a basin area of 282.26㎢ and touches seven cities of kyounggido and some of Seoul Metropolitan area. The situations of Anyang stream have resulted in severe stream water pollution problems. The purpose of this study were to measure the hydraulic characteristics and water quality, to make the countermeasures to achieve the stream water quality, to suggest the future conditions to improve water quality trough the Hydrodynamic and Water Quality Model(WASP4). As the result of Anyang stream water quality forecast, they are follows. Sewerage systems in the watershed of the Anyang stream have to be amended for wrong system and constructed in the upstream area of Anyang stream. Hydrodynamic and Water Quality Model(WASP4) for this study revealed the future water quality of the Anyang stream by computer simulation.