[Objective] To provide a decision basis for low-carbon strategy of land use and land cover change. [Methods] Based on RS and GIS, taking the data source of NDVI and Landsat, the carbon of vegetation and soil system in Shaanxi Loess platform region during 1990-2010 was calculated by the Carnegie-Ames-Stanford Approach(CASA) model. [Results] Large part in the research area was carbon source, however, the carbon sink area were small and mainly distributed in the northern part in Weinan loess platform. During the research period, the carbon source degree in Xianyang loess platform, Baoji loess platform and Xi'an loess platform decreased, whereas, of which in Weinan loess platform and Tongchuan platform increased in some degree. From 1990 to 2010, the high degree carbon source area decreased from 38.22% to 21.13%, middle degree carbon source area were the largest and improved from 57.40% to 67.71%, and the area of low degree carbon source increased from 3.43% to 7.76%.At the same period, the area of carbon sink enlarged from 0.96% to 3.40%. [Conclusion] Cultivated land, forest land and grass land were changed into built-up land were not benefit to the carbon sink, and the enhancing of cropping index benefit to the carbon sink of vegetation and soil system.