China, with its huge population and relatively meager natural resources, fragile ecosystems, plus the unprecedented urbanization and economic growth in terms of speed and scale, is facing severe challenges of sustainability and survival. Addressing these challenges requires that the national land should be planned and used wisely. This research is a pilot project aiming at establishing an ecological security pattern at the national scale that will protect the most sensitive ecological landscapes; and a critical pattern as a strategy for wise conservation and wise development. Critical natural processes are analyzed systematically at the national scale, including headwater conservation, prevention of soil erosion , storm water management and flood control, combating desertification and biodiversity conservation. This study not only has an important impact on China's policy of ecological civilization construction, but also has been widely cited as a classical study in the world.