On the same lead/zinc mine slag，the four plants of seedling stage light birch,buddleia,bamboo reed and Miscanthus floridulus were selected for an outdoor pot experiment.By taking the four plants roots after 200 days growth and slag as the research object,root system features and their effects on slag antiscourability,anti-erodibility and compatibility were studied.Results showed that the underground biomasses of the four plants were in the order of bamboo reed>buddleia>Miscanthus floridulus >seedling stage light birch.Root volume of bamboo reed was significantly greater than other three plants.The four plants had obvious enhancement effect on slag anti-scourability and anti-erodibility.Bamboo reed showed the most significant effect,with the enhancement coefficient of 0.98 for slag anti-erodibility and the enhancement value of 26.63 for slag anti-scourability.A significant positive correlation was found for the relationship between the root biomass of the plants and the decreased rate of slag erosion.