In order to evaluate the feasibility of soil types being used as auxiliary information to improve the spatial prediction accuracy of soil organic carbon in fluvo-aquic soil area, 212 prediction samples and 80 validation samples were collected throughout the Pei County, and the spatial prediction accuracy of the two methods of ordinary kriging (OK) and the kriging combined with soil types information (STK) were compared for soil organic carbon (SOC) content. The results showed that there were great differences for SOC content among the main soil types. The content was highest in silted soil (16.35 g/kg), while the one was lowest in sandy soil (8.58 g/kg). The ones of mixed soil and light saline-alkali soil were between them. The prediction accuracy using OK directly was low due to the great smoothing effect, and the corresponding correlation coefficient and the RMSE were 0.45-8.31 g/kg, while the ones of STK was 0.75-6.02 g/kg, and the RMSE was 20% lower than the former. Furthermore, the SOC spatial distribution from STK reflected the difference of SOC content among soil types better and was closer to the regional reality than the one from OK. It was indicated that STK could reduce the smoothing effect and improve the prediction accuracy by eliminating the difference of SOC contents among soil types. The information of soil type, which was closely related to SOC content, could be used as auxiliary information to improve prediction accuracy of SOC in the alluvial soil areas of North Jiangsu.