Different combinations of grass species were tested to see which ones were most effective for protecting highway slopes. The combination of Agropyron cristatum and Medicago sativa was the best for increasing seedling speed and coverage. Caragana korshinskii and Leymus secalinus showed a significant increase in coverage and plant biodiversity. The combination of Agropyron cristatum, Puccinellia tenuiflora, and Hippophae rhamnoides had the highest increase in aboveground biomass. Different combinations performed better on north-facing slopes versus south-facing slopes. The top-performing combinations were Agropyron cristatum, Puccinellia tenuiflora, and Hippophae rhamnoides, followed by Agropyron cristatum and Medicago sativa, and then Caragana korshinskii and Leymus secalinus.