[Objective]Degradation of purple soil is critical, water loss is serious, and it is difficult to increase and sequester carbon in the soil. In order to explore the impact of carbon source addition on the carbon sequestration of purple soil farmland。[Methods]Purple soil slope cropland in Sichuan Province was selected as the study. Six treatments were set up on 10° purple soil slopes: no fertilization (CK), fertilizer + straw returning (T1), fertilizer + straw biochar (T2), fertilizer + cow dung (T3), fertilizer + organic soil matrix (T4), fertilizer + biochar cow dung and mushroom slag compost (T5), each treatment was repeated 3 times. Analyze the change characteristics of runoff, sediment and carbon content under rainfall and different carbon sources.[Results]The results showed that (1) rainfall over 30 mm and short-term heavy rainfall (16.1 mm·h-1) could lead to surface runoff. The addition of carbon sources notably decreased surface runoff. In comparison with the CK , the flow reduction benefits of T2, T3, and T5 reached 38.64%, 38.61%, and 62.95%, respectively. The sediment erosion in different treatments was observed to follow the order: T1>T4>CK>T2>T3>T5, with the highest reduction of 58.99% compared to the CK . (2) The loss of organic carbon through surface runoff was primarily attributed to sediment organic carbon, which accounted for 67.47~90.43% of the total organic carbon loss. Treatments T2, T3, and T5 were effective in reducing the migration of organic carbon, resulting in a total organic carbon loss reduction of 21.74%, 19.40%, and 49.28%, respectively, compared to the CK treatment. Furthermore, the carbon fractions of T5 treatment, including dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), dissolved total carbon (DTC), and sediment organic carbon, exhibited a reduction in migration fluxes by 70.88%, 70.92%, 37.52%, and 60.07%, respectively, compared to the CK treatment. (3) PLS-PM showed that the C sequestration of soil organic carbon was influenced to varying degrees by rainfall characteristics, soil physicochemical properties, and the addition of different carbon sources.[Conclusion]Carbon sources (T2, T3, T5) reduces the total amount of organic carbon loss. T5 processing organic carbon sequestration stock increases, T2 and T3 reduce the loss of each carbon component of surface runoff, while its organic carbon sequestration stock decreases. It shows that the addition of carbon source can increase the carbon content and reduce the carbon migration, but that the solid stock is reduced, which needs to be verified by long-term experiments. This study holds significant importance in enhancing the fertility of purple soil, maintaining soil carbon balance, and reducing soil carbon loss.