Although the dispersed water supply has solved the problem of domestic use water and drinking water for livestock to a certain extent in karst area of southwest China,the water pollution occurs widely.Through investigation,monitoring and synthetic analysis of water quality of three primary dispersed water supply,it is considered that the water pollution is composed of recharging water pollution and supplying water pollution,belonging to pollution over a plane and dot shaped pollution separately.There are three types of pollution: the main one is bio-pollution such as visible matter and invisible microorganims,the second is physical pollution such as high chromaticity and turbidity,and the last is chemical pollution such as high pH value(8.5) and exceptional ion concentration resulted from refuse and excrement.There are three main contaminative approaches also-they are pollution during rainfall,pollution during runoff containing surface runoff,underground runoff and water transferring,and pollution during water storage and utilization.Finally,countermeasures for water treatment are suggested based on the status of water pollution in dispersed water supply.