In this study, artificial planting (temporal dimension) and field sampling (spatial dimension) experiments were conducted to examine the spatial and temporal variations in soil erodibility through flume scouring of undisturbed soil under the influence of root systems of representative herbal species on the Loess Plateau. The findings indicated in temporal dimension, a marked initial surge, followed by a gradual decline in root densities (expressed as root length density and root surface area density) of Lolium perenne and Medicago sativa over the course of the observational period. Propelled by the root growth, the organic matter content in soil enhanced significantly from 1.65 to 2.74 g/kg in Lolium perenne plot and from 1.53 to 3.37 g/kg in Medicago sativa plot. Meanwhile, cation exchange capacity of soil enhanced significantly from 9.24 to 15.54 cmol/kg in Lolium perenne plot and from 8.63 to 15.91 cmol/kg in Medicago sativa plot. The changes in root characteristics and soil physicochemical properties caused a prompt decline in soil erodibility in both Lolium perenne and Medicago sativa plots during the initial phase of observation, with erosion reduction rates ranging from 35.68% to 54.40%, followed by a phase of progressive stabilization. In the spatial dimension, root densities (expressed as root length density and root surface area density) of Stipa bungeana in Yongshou and Shenmu were significantly higher than those in Ansai. On the other hand, root densities of Artemisia gmelinii in Yongshou were significantly higher than those in Shenmu and Ansai. Changes in the root systems caused the most substantial increase in soil organic matter in Yongshou. In comparison to fallow land, soil organic matter contents in Stipa bungeana and Artemisia gmelinii plots were 43.63% and 97.23% higher, respectively. Furthermore, cation exchange capacity of soil in Stipa bungeana and Artemisia gmelinii plots enhanced most significantly in Shenmu and Yongshou, by 18.87% and 68.21%, respectively. The root characteristics and erosion resistance capacity of soil across different experimental areas indicated that the impacts of Stipa bungeana and Artemisia gmelinii roots on soil erosion were most pronounced in Shenmu, where soil erodibility reduced by 97.50% and 98.61%, respectively. Consequently, the reduction effects of herb roots on soil erodibility are significantly different in both temporal and spatial dimensions on the Loess Plateau. These results contribute to a systematic understanding of the mechanism of plant roots on soil erosion, and provide a theoretical basis for the prevention and control of soil and water loss in this region.