A study was carried out using Geostatistics method to explore the spatiotemporal variability of soil organic carbon (SOC) contents in different layers (0–10, 10–20, 20–30, 30–40, 40–60 cm) in 4 reclamation areas and tidal flat in Rudong County of Jiangsu Province. The results show that the average content of SOC increased with the increase of the reclamation year. SOC content displayed an increasing trend from beach to inland with local effects according to different soil layers and a decreasing trend with soil depth in a soil profile. The main controlling factors of SOC contents were different among different soil layers, and the topsoil was more driven by people activities. From the perspective of land use, SOC content of cultivated land was higher than that of aquaculture body. SOC content was significantly positively correlated with soil fine particles especially silts, and negatively correlated with pH and total salt. The above results indicate that the reclamation intensified the spatiotemporal hetero?geneity of SOC, which is of great significance for the guidance of rational and orderly development and utilization of tidal flat.