The study on forest and water quality is one of the main subjects of forest hydrology. Civil and foreign researches have indicated that the forest can well purify the water flowing into rivers, lakes and reservoirs. The vegetation in forest can not only filter and intercept pollutants in water, but also release some nutrition elements. The study on forest and water quality is of great significance to protect water resource and prevent non-point source pollution. The study on forest and water quality is one of the main subjects of forest hydrology. Civil and foreign researches have indicated that the forest can well purify the water flowing into rivers, lakes and reservoirs. The vegetation in forest can not only filter and intercept pollutants in water, but also release some nutrition elements. The study on forest and water quality is of great significance to protect water resource and prevent non-point source pollution.