[Objective]This study aims to investigate the impacts soil erosion-deposition processes on soil organic carbon (SOC) fractions and their underlying interaction mechanisms, to enhance understanding of carbon stock management strategies and SOC response mechanisms in the black soil region in Northeast China’s cultivated land. [Methods]The research focused on typical sloping farmland in Binxian County (thin-layer black soil) and Keshan County (thick-layer black soil). The 137Cs tracing technique was employed to quantitatively assess soil erosion intensity, clarify the differences and trends in SOC fractions under varing erosion intensities, and reveal the mechanisms underlying changes in SOC fractions induced by soil erosion. [Results]Results showed that the soil erosion modulus in the thin-layer black soil area was 2822.99 t/(km2·a), while in the thick-layer black soil area it was 2174.74 t/(km2·a). Soil erosion-deposition rates were found to be the primary drivers of SOC fractions changes. SOC fractions decreased significantly with increasing soil erosion rates, exhibiting a strong negative linear relationship. The loss rates of different SOC fractions were ranked as follows: EOC > POC > MBC > DOC. [Conclusion]Total nitrogen (TN) was identified as a key factor influencing the distribution of SOC and its fractions, while the C/N ratio, clay content, and sand content also had significant effects. These findings provide a scientific basis for carbon stock management and erosion control in the black soil region.