Grassland recovery and land reconstruction in the Loess Plateau are critical constituents of regional ecological construction. Exploration of soil organic carbon density (SOCD) changes during the process of grassland recovery is important in assessing environmental changes, as well as suggesting estimates of soil carbon sequestration in the dissected area of wind-water erosion in north China. Soil was found to be a slight carbon sink during recovery processes in the agro-pastoral area of the northern Loess Plateau with SOCD, being (2.11 kg C m^-2) in scrubland > (1.95 kg C m^-2) in secondary natural grassland > (1.91 kg C m^-2) in artificial grassland > (1.69 kg C m^-2) in abandoned farmland and > (1.68 kg C m^-2) in farmland. However, these differences were not statistically significant, suggesting that impacts of vegetation recovery on SOCD were relatively slight and that the potential for CO2 sequestration in local soils is not large. Changes of SOCD had been studied in Medicago sativa grasslands of different ages and in the secondary natural grassland of abandoned land in Liudaogou catchment, in Shenmu county of Shaanxi province. Results showed that SOCD were generally low, ranging from 1.18 to 2.81 kg C m^-2. Values of 1.4 kg C m^-2 are also typically found in desert areas and such values are significantly lower than values for the central Loess Plateau. In the central Plateau, values range from 4.46 to 9.95 kg C m^-2, with a national average of 11.5-12.0 kg C m^-2 for China. SOCD increased at varying rates when land use patterns changed from farmland to artificial grassland or changed further to the secondary natural Stipa bungeana grassland. SOCD under well-developed Stipa bungeana grassland improved only slightly to 2.20 kg C m^-2. Vertical changes in SOCD revealed that soil carbon was mainly sequestrated in the surface layer of 0-20 cm. Furthermore, SOCD in this layer was significantly correlated with an average value for the whole 0-100 cm profile. So SOCD, in the 0-100cm layer, can be well estimated using values for the 0-20 cm layer, with an estimation error of only 9.9 % (0.18 kg C m^-2).