[Objective] A large number of red clay slopes exist in Guizhou Province, and soil erosion and shallow landslides are prominent problems. The use of herbaceous plants to protect red clay slopes is of great significance for shallow landslide management and soil and water conservation in Guizhou Province, but there are fewer related studies. [Methods] With red clay slope as the research object, Cynodon dactylon and Vetiver grass were selected as slope protection plants. The slope protection effect of the two herbaceous plants was investigated through planting test, root tensile test, straight shear test, and indoor simulated scouring test. [Results] ① Within 150 days of planting, both herbaceous plants grew steadily and the tensile strength of the root system continued to increase. From 30 to 150 days of growth, the maximum tensile strength of Cynodon dactylon increased from 0.84N to 8.59N, and that of Vetiver grass increased from 4.78N to 89.89N. ② Comparing the rootless soil at 120 days of growth, the cohesion of Cynodon dactylon root-soil complex increased by 91.1% and the angle of internal friction by 12.45%; the cohesion of Vetiver grass root-soil complex increased by 107.47% and the angle of internal friction by 12.74%. ③ Comparing the bare slope at 150 days of growth, the runoff rate of Cynodon dactylon slope decreased by 45.02% to 54.15%, the sediment yield rate decreased by 58.3% to 93.85%, and the 60-min cumulative sediment yield decreased by 81.02%; the runoff rate of Vetiver grass slope decreased by 35.46% to 46.48%, the sediment yield decreased rate by 46.8% to 89.44%, and the 60-min cumulative sediment yield decreased by 74.61%. [Conclusion] Both herbaceous plants have excellent soil consolidation and slope protection effects on red clay slopes, with Vetiver grass having a more pronounced effect on the increase in soil shear strength, and Cynodon dactylon having a more significant effect on soil and water conservation.