The influence of the quality of all kinds of pipeline materials of wate-supply on water quality is introduced,the influence includes the dissolution of organic and inorganic matterials of water-supply on water quality is introduced,the inluence includes the dissolution of organic and inorganic matters,the degree of the difficulty of the growth of growth ring,chlorine residue decay,the impurities from coating materials come-off of the pipeline and their concentration increase and so on,and therefore the measures such as impoving the water quality and stability and stability of undertaken water,renewing water-supply pipeline system and maintaining old water-supply pipeline system are put forward.