[Objective] The effects of parcel-border features (PBFs) on the calculation of the slope length factor and soil erosion rate of small watersheds in a black soil region were studied in order to provide a basis to improve the precision of soil erosion prediction in the region.[Methods] Two typical small watersheds were selected. Field survey and digital elevation model analysis were used to calculate the slope length factor considering the PBF, and the PBF was ignored.[Results] The slope length factor could be overestimated by 18% and the soil erosion rate by 31%, on average.[Conclusion] It is necessary to consider PBFs for the slope length factor and soil erosion rate calculations of small watersheds in black soil region. Similarly, under other factors, it would be necessary to consider PBFs when the slope gradients are larger and the intervals between cross-slope PBFs are smaller.