[Objective] Elucidating the effects of soil erosion-deposition on the soil quality of slope croplands in the black soil region of northeast China can provide an important scientific basis for the conservation and sustainable utilization of black soil resources. [Methods] Two slope croplands in the thick-layer black soil areas of Keshan County，Heilongjiang Province，were selected. The ¹³⁷Cs tracer technique was employed to estimate soil erosion rates. Based on the minimum data set（MDS）method，soil quality evaluation indicators were constructed to analyze the effects of soil erosion-deposition on soil quality in slope croplands of typical thick-layer black soil regions. [Results] 1）The soil erosion-deposition rates of slope cropland in the study area ranged from -1 563.2 to 7 916.1 t/（km²·a），with an average erosion rate of 2 669.0 t/（km²·a）. Moreover，in terms of spatial distribution， severe erosion occurred in the middle and lower parts of the slope，and mild-moderate erosion occurred at the slope top and in the middle and upper parts. Sediments were deposited in the 50 m section at the slope bottom，and the most severely eroded areas were located in the 120―170 m slope section. 2）MDS for soil quality evaluation was constructed，encompassing soil clay（Clay），soil organic carbon（SOC），total phosphorus（TP），available nitrogen（AN），microbial biomass carbon（MBC），and β -1，4-glucosidase（BG）. Moreover，the MDS could serve as a substitute for total data set（TDS）and more accurately reflect the soil quality status of croplands in the study area. 3）In the erosion zones of the study area，the soil quality index（SQI）was significantly negatively correlated with soil erosion rates（p<0.01）. In the deposition zones，the SQI showed an insignificantly positive correlation with deposition rates. In the two sample plots，the SQI in the erosion zones reduced by 13.3% on average compared to the deposition zones，and the spatial distribution of SQI showed an opposite trend to that of soil erosion rates. [Conclusion] Soil erosion is the key driving force for soil quality degradation of slope croplands in the study area.