Cultivated slopes are the major soil loss area and the major river sediment source in the Three Gorges Reservoir region. However, reliable studies of soil erosion and sedimentation in the region are limited and the fundamental research on soil erosion is inefficient. A study was carried out to investigate soil erosion on a cultivated slope in the region using ¹³⁷Cs technique. Preliminary results showed that the ¹³⁷ Cs reference inventory of the study catchment was estimated to be 1 420.9 Bq/ m². The ¹³⁷ Cs inventories of gentle cultivated slope with a mean degree of 11.4°ranged between 398.5 and 1649.6 Bq/ m² and the average value of slopelengt weighted was 816.0 Bq/ m². Soil erosion rate on the cultivated slope was estimated by revised simplified mass balance model. Soil erosion rate on he study slope ranged between - 3358.8 and 4937.4 t/(km²·a) and the average value of slope length weighted was 1 294. 6 t/ (km²·a) . Influenced by the tillage, soil erosion rates in two slope segments decreased downslope and deposition occurred at the bottom of slope. The lower soil erosion rate is because the cultivated slope has a gentle gradient. On the other hand, a series of tillage method are adopted by the local farmers for preventing soil and water loss efficiently, which greatly reduces soil erosion.