Objective To know the drinking water quality in villages of Tongzhou District,Beijing and provide the basic data for government. Methods 623 wells in 455 villages were sampled in 2004 and the water samples were tested with the national standard methods. Results 166 of 623 water samples were up to standard,the qualification rate was 26.65%. The drinking water quality of all villages was different,in Maqiao(58.62%) and Liyuan(76.92%) it was better than that in Xiji,Huoxian,Zhangwan,Songzhuang. The qualification rate in Xiji was only 10.26%. In the present investigation,24 water quality parameters were tested and 14 parameters exceeded the limit,such as NH3-N,iron,total bacterial count,coliform group,fluoride and arsenic. Some sanitary problems were also found. Conclusion The ground water in Tongzhou has been contaminated,especially the shallow layer ground water,more attention must be paid to improvement of drinking water quality in these villages.