Soil organic matter (SOM) is a key index in estimating soil fertility and soil C sequestration. Consequently, the study on temporal and spatial variability of SOM is of great significance to assessing regional soil C sequestration potential and realizing sustainable utilization of soil resources. For this research, Jiangsu Province, East China was selected as a subject for case study and comparative study was done of the data of the Second National Soil Survey and the data collected in 2006, using the geostatistic and GIS technologies, to explore temporal and spatial variability of SOM in the surface soil layer (0 ~ 20cm) of the province during the period (1980 - 2006), and its driving forces, as well. Results show that the mean SOM content increased from 16.55 ± 8.50 g kg-1 in 1980 to 18.31 ± 8.32 g kg-1 in 2006, and its coefficient of variation decreased from 51.36% to 45.44%. The variograms of SOM of the years both fitted the exponential model, with nugget coefficient rising from 51.85% to 56.52%, suggesting that the effect of stochastic variability of SOM content intensified and spatial autocorrelation weakened. The codomain decreased from 71.55 km to 37.83 km, indicating decreasing spatial autocorrelation distance. A general trend was observed that soils high in initial SOM content decreased in the content and vice versa, and the increment reduced in margin from north to south of the province. The application of large volumes of chemical fertilizers improved crop production, and increased soil biomass from crop leftover and roots. The extrapolation of straw incorporation brought large volumes of organic matter into the soil, contributing to accumulation of SOM. Changes in land use brought about changes in SOM. Reclamation of land into paddy fields, upland and forest lands increased SOM content and vice versa.