A total of 550 topsoil samples were collected from farmlands in Mengcheng County, a typical area of the Northern Anhui Plain for determination of soil organic carbon (SOC) content and further analysis of its spatial distribution and variability in the area in 2011 by means of statistics, geostatistics and geographical information system (GIS) technology. Results show that SOC contents in the farmlands ranged from 4.04 to 21.98 g kg^-1 with an average of 10.41 g kg^-1, and an variation coefficient of 24.12%, moderate in variation degree. The SOC semivariance model was a spherical one. Moreover a strong spatial autocorrelation of SOC content was observed. In spatial distribution SOC contents were generally high in the northeast, central and southwest parts of the county and varied sharply within the scope of the county, showing a trend starting from the northwest of gradually rising and then gradually declining towards the southeast, such a spatial variation was attributed mainly to mechanical composition (silt and sand) of the soil and then incorporation of straw.