Objective To research the effect of reverse osmosis membrane and pipeline in water treatment system.Methods A formal questionnaire was prepared and accounted in 20 hospitals' Hemodialysis Centers in 2006 in Changsha.Four points of hemodialysis water of water treatment system were selected,which not only acquired easily but also represent polluted situation:tap water,reverse osmosis water 1(prepare B fluid sampling point),reverse osmosis water 2(go into dialysis machine sampling point),dialyser entrance dialysate sampling point,to detect endotoxin.Results The sanitary quality of the dialysate in hospitals was associated with the using time of water system,timely exchange and disinfection of the water treatment system,whether there were deep space and water storage tank in the channel design.Conclusion Double osmosis systems were superior to one osmosis systems in Hemodialysis system of water treatment system.