【Objective】Farmlands on long gentle slopes of black soil in Northeast China is the main source of soil erosion. Soil erodibility is an important factor affecting soil erosion. The soil erosion process in the black soil region of Northeast China is characterized by overlapping and/or coupling of wind-hydraulic-gravity-freeze-thaw, multiple in force and in process. In spring, freezing and thawing accompanies melting water, and temperature fluctuation and freezing and thawing are the dominant factors affecting soil properties, while in summer and autumn, water erosion is the main form of erosion and rainfall runoff and dry-wet alteration are the two leading factors. However, so far little has been reported in the literature about field experiments on soil erosion resistance in the black soil region under the multi-forced compound erosion, thus making it hard to effectively implement the task of controlling the multi-forced compound erosion. 【Method】On a typical cultivated long gentle slope in the Keshan Farm in Heilongjiang Province, a 150 m long section of the slope was delineated along the same direction as the farmland ridges go from south to north. Soil samples were collected from the 0～30 cm soil layer of the slope at sampling sites 30 m apart along the slope. Soil shearing force of undisturbed soil was determined in April and September 2018. At the same time, the collected soil samples were analyzed for content of water-stable aggregates with the Le Bissonnais method via slow-setting and mean weight diameter (MWD), geometric mean diameter (GMD) and mass fractal dimension (D) of the soil aggregates were measured in an attempt to characterize soil erodibility parameters of the long gentle slope of black soil.【Result】Results show that in terms of shearing force, MWD, GMD, D and content of >0.2 mm soil aggregates, the sampling sites exhibited a decreasing order of 0 m > 30 m > 150 m > 60 m > 120 m > 90 m in spring, and generally an order of 30 m > 0 m > 150 m > 120 m > 60 m > 90 m in fall, which indicate that the soils in the middle of the slope at 60 m, 90 m and 120 m are quite low in soil erosion resistance, and that the slope varies with posiiton of the sampling site in strength of soil erosion, sediment transport and deposition. And soil anti-erodibility increases with soil depth. MWD and GMD is 1.27 times and 1.37 times as high in fall as in spring, respectively, and the content of >0.2 mm soil aggregates and shearing force is higher in autumn than in spring, but D is in a reverse trend, which suggest that the soil erosion resistance of the long gentle slope of black soil is higher in fall than in the spring. The correlations between the indices of water-stable aggregates were significant, but they have nothing to do with shearing force. Soil water-stable aggregates can be used as a stable index to assess soil erodibility. Shearing force is not so good when used as an index for the assessment because it is not stable, which is mainly attributed to its variability with soil properties, susceptible to and complex in change, especially under the influence of freeze-thaw erosion force. As the change of soil erodibility has certain uncertainties, it calls for further in-depth studies on impacts of soil shearing force on soil erodibility on long gentle slopes of black soil in Northeast China.【Conclusion】To control soil erosion in cultivated slopes of black soil in the region, focuses should be laid on adoption of erosion controlling practices in spring, like reducing length of the slope and adopting corresponding soil and water conservation measures in the middle of the slope. Soil water-stable aggregates can be used as a stable index in assessing soil erodibility in the black soil region of Northeast China. Shear force is not so good as soil water stable aggregates when used as index. The findings of this study may be used as a scientific basis for prevention and control of compound erosion in cultivated long gentle slopes of black soil in Northeast China.