Water quality indexes such as ammonia nitrogen, nitrate nitrogen, chloride ion, the total solute content, conductivity, salinity, dissolved oxygen, pH and chlorophyll content were measured by Hydrolab water quality surveymeter through laying monitoring sites evenly on five park lakes (North Sea park, Summer Palace, Yuyuantan park, Taoranting park, Chaoyang Park) within five rings of Beijing. The paper analyzed the situation of water environment in lakes of park from three aspects such as inorganic ion content, cleanliness and eutrophication, and then conducted a comprehensive evaluation on water environment quality in the parks of Beijing by using the gray correlation model. Overall, water quality of the Summer Palace is the best and belongs to class I water.Water quality of the North Sea park and the Yuyuantan park is better and belongs to classⅡwater.Water quality of the Chaoyang park is worse and belongs to class Ⅳ water .Water quality of the Taoranting park is the worst and belongs to classⅤwater.The monitoring and evaluation of water environment in lakes of park can provide an important basis for protection and management of water body in parks and has important significance for parks to fully play its recreational function.