Abstract: According to the data of water consumption from 1980 to 2000 in China,this paper analyze simply the driving factors for water demand,and construct a model for the case study on the contribution ratio of every driving factor changing water demand.The main conclusions involve:(1) The rise of industrial and residential water consumption is the direct cause of water consumption increase;(2) The top fourth positive driving factors are the increase of industrial production value,irrigation area,population,and area of forest,herd and fishing.The decrease of farm irrigation quota plays a first important role in constraining water demand while the decrease of industrial water consumption quota plays the second one;(3) Although population rise is the main contributor of residential water demand increase in North China,the increase of the average residential water consumption quota is more important in South China;(4) Industrial scale enlargement is the main driving factor for the industrial water demand,and the decline of water consumption of unitvalue is quite serious in North China; And(5) variation of the farm irrigation area has great influence on the farm water demand.