Abstract: The authors first describe the origin, characters and harmfulness of non-point source pollution of water environment, analyze the research method for non-point source pollution and review the development of its mathematic model. With the advance of geographic information system (GIS), remote sense(RS) and global position system (GPS), 3S technology has become an important tool for studies on the non-point source pollution. Finally, according to the mechanism of causing non-point source pollution, some effective protection measures in both technology and management are proposed to control the non-point source pollution.