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In order to better understand the effects of tillage erosion on carbon cycle in the sloping farmland, responses of soil organic carbon and aggregate associated carbon to soil erosion were explored in a mountainous region of northern Sichuan Basin, southwest China, with 137Cs tracer and laboratory analysis method. The results showed soil loss was found in upslope where 137Cs concentrations were lower (soil erosion rates were greater), whereas soil deposit occurred in the bottom of sloping farmland where 137Cs concentrations were higher (soil erosion rates were less). Not only water erosion but also tillage erosion contributed to soil losses. Tillage erosion played an important role in sloping farmland soil redistribution, average tillage erosion rate in upslope was 63.22t/(hm2·a）, occupying 94.61% of total soil erosion. Soil deposit rate was 23.94t/(hm2·a）in low positions. Soil erosion resulted in the lowest ＞2000μm, 250～2000μm and 53～250μm size aggregates, and created the highest ＜53μm aggregate fraction in upslope. Meanwhile, soil organic carbon and aggregate associated carbon content and stock were significantly lower in upslope positions than these in bottom slope positions. There was significant correlation between soil organic carbon, content of aggregate associated carbon and 137Cs inventory, suggesting that soils were more fertile in bottom positions than in top positions due to soil redistribution by soil erosion. Therefore, fertilization management strategies should involve spatial variation of soil properties in purple soil of hilly sloping farmland.