With the contradictions of water use and supply are increasingly intensified, a large quantity of water for the ecological environment and agriculture are crowded out by urban. For easing the water conflicts and improving the ecological environment, to carry out water-saving city construction is imperative. In this paper, the integrated water resources supply and demand of Tianjin in 2005-2030 are simulated under different modes of the basic program, industrial reconstruction,price control, quota adjustment and urban non-conventional water sources utilization. The effect of water-saving incentive mechanism is analyzed quantitatively. The result obtained by the paper may provide a reference for further improving the city construction and management of water saving city.