China with expanse area has significant variability in carbon sources and sinks of terrestrial ecosystems and their driving factors, so it is necessary to determine scientifically the prior regions ( PR_C) for reduction of carbon source and enhancement of carbon sink,and to propose for extending the measures of reduction of carbon source and enhancement of carbon sink in China. In this study, after collecting the available studies on the distributions of net primary productivity (NPP), biomass, soil carbon, soil respiration, and climate and human activities, we analyzed the distribution of carbon source and sinks in terrestrial ecosystems in China and their driving forces, posed five principles,including maximization of carbon storage,genesis of carbon pool,relative consistency within region and areas concentrated and connected, to make up the procedure to determine the PR_C. 19 prior regions (PR_C ) were identified for reduction of carbon source and enhancement of carbon sink in terms of distributions of carbon sequestration potential and carbon storage stability over China. Included are 6 forest regions for carbon emission reduction, 6 forest regions for carbon enhancement, 4 grassland regions for carbon emission reduction, 1 grassland region for carbon enhancement, and 2 agricultural regions for carbon enhancement. The delineated prior regions occupy 2. 23 millions square kilometers, accounting 23% of the whole land of China. The prior regions store 5. 68Pg vegetative carbon, which is more than 40% of vegetative carbon pool in the whole China land, and 15. 7Pg soil carbon, which is about 8% ~ 23% of soil carbon in the whole China land. Furthermore, the policies for managing each prior region were suggested. These PR_C determined in national scale will be the key and prior regions for extending carbon sequestration measures and enhancing ecosystem services. The results will stimulate the accomplishment of national targets of carbon reduction in 2020 and guide the national space allocation for adaptation climate change and protection of environment.