Objective  This study aims to analyze the distribution characteristics of soil organic carbon (SOC) in paddy soil profile and its influencing factors according to the genetic horizon.

  Method  By measuring SOC content in each occurrence layer of 58 paddy soil profiles in Hunan Province, the SOC distribution characteristics in the occurrence layer of paddy soil profiles were determined, and to further identify the factors influencing the spatial variation.

  Result  ①The average SOC content in the entire paddy soil profile was 9.30 g kg⁻¹, in the genetic horizon, the cultivated horizon had the greatest content, with the average of 22.94 g kg⁻¹, followed by plow pan and subsoil layer, with the averages of 15.09 g kg⁻¹ and 6.93 g kg⁻¹. ②Among the different soil parent material, the paddy soil developed from the weathering product of limestone had the largest SOC in each generation layer. For different textures, the overall performance of SOC in each genetic horizon increased with an increase in proportion of silt. ③Kriging interpolation analysis indicated that the SOC of each genetic horizon had high and low values in the southwest and low in the northeast, respectively. ④Geographic detector showed that the soil bulk density generally exhibited the greatest explanatory power in each genetic horizon. Furthermore, the interaction forces between the soil bulk density and other factors were clearly strengthened．

  Conclusion  Significant differences in SPC content in paddy soils at teach genetic horizon of the profile. The spatial distribution of SOC in paddy soils is shaped by the interaction of multiple factors, and bulk density showed the most significant explanatory power for the SOC in genetic horizon.