The water resources in China are characterized by uneven regional and seasonal distribution. These features result in frequent droughts and floods, and unstable agricultural production. Per capita available water resources, ranking 108th worldwide, is very low although the country ´ s total is 2 810 km³. Regional distribution of water resources does not match that of land resources and an imbalance between water demand and supply has occurred seriously. With the growth of population, the industrial and urban water demand increased rapidly. The development of irrigation, affected by the lack of water resources, has basically been brought to a standstill. The sustainable social and economic development is facing greater challenges than any other country of the world. Moreover, owing to continuous deterioration of water environment and lack of construction funds, the water resources problems have become important constraints of social and economic development in China. This paper discusses the water problem and the countermeasures for sustainable development in 21st century.