Inthemodernbuildingconstruction,thewatersupplyanddrainagesystemplaysanimportantpartinarchitecture.Andpeoplepaymoreandmoreattentiontoit.Thispaperexplainsthatthedesigningideasofwatersupplyanddrainagesystemhavegreatlyimprovedbecauseofthetechnologicaldevelopment,especiallyinrecentyears,thedemandsofenvironmentalprotectionhavehighlyincreased.