Herbaceous plant roots are crucial in combating soil erosion due to their complex network structure and strong mechanical properties. However, current research does not establish an association between root morphological and mechanical characteristics and soil erosion. In this study, we selected eight typical herbaceous plants from the Loess Plateau. 240 undisturbed soil specimens were used to measure the soil resistance (reflected by rill erodibility) under six shear stresses. results showed that rill erodibility ranged from 0.008 to 0.497 m s-1 in the eight grasslands, and the rill erodibility of grasslands was 10-99% lower compared to bare soil. Plants with taproot systems demonstrated higher rill erodibility, a 5.86-fold increase compared to fibrous root systems. Root geometrical, morphological, and mechanical characteristics varied across the eight herbaceous plants, indicating the influences induced by plant roots on soil resistance from diverse perspectives. Rill erodibility decreased exponentially with root mass density, root surface area density, and root length density. Moreover, power functions were found between rill erodibility and root morphological (fractal dimension and topology index) and mechanical (root tensile strength and cohesion) characteristics. Although root geometrical, morphological, and mechanical characteristics can all influence soil resistance, the morphological characteristics exert the greatest impact. The results of the variance partitioning analysis indicate that root geometrical, morphological, and mechanical characteristics explained 98% of the overall variance in soil resistance, and morphological parameters accounted for 53%, followed by mechanical (5%) and geometrical (1%) characteristics. The total effect of root geometrical characteristics on soil resistance was negative effect, and morphological, mechanical characteristics was positive effects. Among these root characteristics, the topology index contributed the most to soil resistance. Lastly, rill erodibility was simulated by surface area density, topology index, and root cohesion. This study provides a mechanistic understanding of how different root characteristics regulate soil resistance, offering a theoretical basis for vegetation selection and root-based strategies to control soil erosion in the Loess Plateau and similar ecologically vulnerable regions.