China，with its huge population and relative meager natural resources, fragile ecosystems, plus the unprecedented urbanization and economic growth in terms of speed and scale, is facing sever 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 ecological security patterns at the national scale that will protect the most sensitive ecological landscapes and critical pattern as a strategy for wise conservation and wise development. Critical natural processes are analyzed systematically at the national scale, including headwater conservation, soil erosion prevention, storm water management and flood control, desertification combating and biodiversity conservation. Individual security patterns for safeguarding each of these natural processes are identified and then integrated into an overall ecological security pattern. Three levels of National Ecological Security Pattern are defined, the lower security level, the moderate security level and the higher security level, which account for 35.7%, 65.1% and 84.9% of the national land respectively. This study is expected to provide a scientific basis for the under\|going national function zoning and land use planning at the national scale.