Groundwater quality in Beijing North Canal Watershed was evaluated by selecting seventeen indicators and taking comprehensive quality evaluation method of groundwater quality that is recommended by Chinese standard. Spatial distribution maps of groundwater quality were drawn by using spatial analysis function of map GIS and employing Kriging interpolation method, and spatial distribution characteristics, cause of characteristics and main influence indicators were analyzed. The results show that groundwater quality in Beijing North Canal Watershed takes on characteristic of gradual deterioration from northwest to southeast , which is caused by natural conditions and human factors. The main indicators of poor water quality and poor range are total hardness, total dissolved solids, nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, iron and manganese.