Abstract:  In this study, the spatial heterogeneity of soil organic carbon content in citrus orchards was studied. The relationship between organic carbon content and other soil physicochemical properties, topographic characteristics and climate variables was discussed. This will provide a scientific basis for improving economic forest ecosystem services. Field soil sampling was carried out in the citrus distribution area of Zigui County. The main influencing factors of soil organic carbon were simulated and the spatial distribution of soil organic carbon content was predicted based on the random forest algorithm and geographically weighted regression model in combination with eight topographic variables, two climate variables and thirteen soil variables. The results show that the average contents of soil organic carbon in 0-20 cm (topsoil) and 20-40 cm (subsoil) in the study area were 11.95 and 9.01 g·kg^-1, respectively. The soil organic carbon content on the northern bank of the Yangtze River (9.24 and 7.56 g·kg^-1) was lower than that on the southern bank of the Yangtze River (14.48 and 10.36 g·kg-1), while the coefficient of variation on the northern bank (0.53 and 0.66) was higher than that on the southern bank (0.45 and 0.58). The relative contribution of influencing factors to the spatial distribution of soil organic carbon content was different among soil layers. The relative contributions were in descending order: total nitrogen (53.0%) > total potassium (11.9%) > available nitrogen (11.4%) > mean annual precipitation (7.6%) > soil moisture content (7.3%) > mean annual temperature (5.1%) > elevation (3.7%) in topsoil; total nitrogen (69.7%) > available nitrogen (14.2%) > bulk density (7.5%) > plane curvature (4.3%) > total potassium (3.8%) > fine sand (0.6%) in subsoil. Based on the geographically weighted regression model, the predicted values of soil organic carbon content in topsoil and subsoil were obtained, i.e., 6.92-16.85 and 5.76-13.75 g·kg^-1, respectively. The local coefficients of determination of soil organic carbon content were 0.662-0.692 and 0.596-0.642, respectively. The soil organic carbon content also exhibited the characteristic of “high in the north and low in the south in topsoil, and high in the east and low in the west in subsoil”. The measured and predicted soil organic carbon contents of citrus orchards in Zigui County showed obvious spatial differentiation characteristics: the southern bank > the northern bank and the topsoil > the subsoil. The influence of soil physicochemical properties on the spatial distribution of regional organic carbon content was higher than that of topographic and climate factors. Particularly, total nitrogen had the largest relative contribution. Therefore, regulating soil physicochemical properties such as soil nitrogen in economic forests is beneficial to increasing soil organic carbon storage.