According to United States Global Change Research Program prepared by the subcommittee on Global Change Research of the Committee on Environment and Natural Resources Research, this paper introduces the goal, activity and highlight of carbon cycle study of the program. The main goal of USGCRP' s Carbon Cycle Science Program is to provide synthetically understand of carbon sources and sinks. The initiative focuses on determining the location, magnitude, and cause of carbon sink in North America, and how North America compares to other key regions. Because estimation of the Northern Hemisphere sink range widely, a program of USGCRP integrated observations, process research, and modeling will narrow this range and provide a more accurate estimation of the North America terrestrial
sink and its variability. USGCRP' s strategy will be to combine research approaches from the atmospheric,oceanic, terrestrial and human dimension aspects of the carbon cycle, provide information on various temporal and spatial scales, necessary to providing an accurate picture of the current state of the terrestrial carbon sink over North America. USGCRP will develop new technologies for measuring the atmosphere-land-ocean carbon system. Different satellites and sensors will be launched to provide improved global measurements of vegetation and accurate data of ocean biology. An improved, long-term, integrated monitoring strategy for carbon measurements will be suggested in the atmosphere, ocean and land ecosystems.Because of US' leading position on this field, this paper implies basically the international new tendency on carbon cycle study. Meanwhile, directions on carbon cycle research in China were analyzed.