Abstract: Soil organic carbon(SOC)represents the largest organic carbon pool in the terrestrial biosphere. Fluctuations in its content not only exert a profound influence on the global climate but are also directly linked to ecosystem health and stability. As a critical agro-pastoral ecotone, the Liaohe River Basin is characterized by relatively low SOC content and a fragile ecological condition. Based on soil geochemical survey data of the Liaohe River Basin, this study employed geostatistical methods and ArcGIS technique to analyze the spatial distribution characteristics of soil organic carbon density(SOCD), to explore the relationships between surface SOC content and parent material, climatic conditions, and topography, and to evaluate the relative importance of various factors influencing SOCD using the random forest model. The results indicate that the average surface SOCD(0-20 cm) in the Liaohe River Basin is 1.96 kg/m², ranging from 0.01 to 41.54 kg/m². The spatial distribution exhibits moderate spatial autocorrelation at a large scale, resulting from the combined influence of structural and stochastic factors. Overall, the SOCD shows a decreasing trend from southeast to northwest and from plains to the western inland hilly areas. Sunshine duration, precipitation, altitude, temperature, and wind speed are key impact factors to the SOCD, while parent material, land use type, soil type, and pH have minor effects. A significant positive correlation was found between SOCD and precipitation, whereas negative correlations were observed with sunshine duration and temperature. These findings suggest that the formation and variation of SOC stocks represent a complex ecological process, and the underlying mechanisms require further investigation.