Soil samples were collected from 0–20 and 20–40 cm depths in different slope sites (top of slope, middle of slope, and foot of slope) of Tamarindus indica plantation to analyze the variations of soil organic carbon (SOC), readily oxidizable carbon (ROC), particulate organic carbon (POC) and dissolved organic carbon (DOC). The results showed that SOC of Tamarindus indica plantation was the highest at top of slope and the lowest at foot of slope. SOC was enriched in topsoil (0–20 cm) at top and middle of slope, ROC, POC and DOC contents changed similarly as SOC, and there were extremely significant positive correlations between SOC and active soil organic carbon of ROC, POC and DOC (P<0.01). The proportions of ROC, DOC and POC in SOC were 33.11%–47.00%, 1.27%–1.89%, and 20.10%–26.51%, respectively. Soil carbon at the foot of slope was the most stable, which is benefit to organic carbon accumulation. Thus, planting Tamarindus indica, a native tree species, in the dry and hot valley of Yuanjiang has a beneficial effect on SOC accumulation, it can promote the function of soil as organic carbon pool in this area.