Based on the summing up the past experience and looking for the future, the author advances some new thought on water-related human activities in the new century, and cites enormous cases and data to testify them and holds that in the water-related human activities in the 21st century, the relationships among human activities, water-body dynamic states, ecological environment, economic development and social progress should be properly dealt with. Their relationships can be called as： human-water-environment-development-society relationship for short. Furthermore the author considers that it is important to master the long-term effect of human water-related activities and other productive activities upon water-body dynamics as well as the inverse actions. Water-saving and water quality protection should be put in the first and important position of water-related human activities. Research, exploration and utilization of waters in atmosphere and sea should be intensified. Afforestation and protection of existing forest, — the “green reservoir” should be regarded as decisive measures to protect and restore water sources, which should be put into the implementation. The relationship among farmland, forest and water-cover area should be properly dealt with, in which the area of water-cover should be protected and enlarged properly. Also, marsh must be properly protected, and great concerns must be shown for small streams and small waterbodies. In the future water-related human activities, the human beings should adapt to and take advantage of the nature rather than against it, make full use of information technologies of various kinds to establish “informative water resources” Through understanding and mastering of hydrome-terological phenomena, set up adjustable agriculture 一 “strainable agriculture”，thereby find proper strategic to save water in the sectors with high water-consuming while obtaining enough agriculture produces.