[Objective] This study aims to investigate the impacts of soil erosion-deposition processes on soil organic carbon（SOC）fractions and their interaction mechanisms，to enhance understanding of carbon stock management strategies and SOC response mechanisms in the cultivated black soil region of northeast China. [Methods] The research focused on typical sloping cultivated land in Bin County（thin-layer black soil）and Keshan County（thick-layer black soil）. The ¹³⁷Cs tracing technique was employed to quantitatively assess soil erosion intensity，identify differences and trends in slope SOC fractions under different erosion intensities，and elucidate the mechanisms by which soil erosion affects SOC fractions. [Results] The annual average soil erosion modulus was 2 822.99 t/（km²·a）in the thin-layer black soil area and 2 174.74 t/（km²·a）in the thick-layer black soil area. Soil erosion-deposition rates were found to be the primary drivers of changes in SOC fractions. SOC fractions decreased significantly with increasing soil erosion rates， exhibiting a significant negative correlation. The loss rates of different SOC fractions were ranked as follows：EOC > POC > MBC > DOC. [Conclusion] Total nitrogen（TN）is identified as a key factor influencing the distribution of SOC and its fractions，while the C/N ratio，clay content，and sand content also have significant effects on the distribution of SOC fractions.