Eco-toxicology effects of compound stress of Cu, Cd, Pb, Zn and As on growth, chlorophyll content and protective enzyme of Juncus Effuses were studied using pot culture. Concentrations of the heavy metals in the soil were designed according to the State Soil Environmental Quality Standard. Considering practical application, soils contaminated with tailings and wastewater from Lead/Zinc mining were also used in the experiment. Results showed that biomass of the ground part of Juncus Effuses was inhabited to a certain degree. When the dosages of the heavy metals added to the soils were close to Grade II Criteria of the State Soil Environmental Quality Standard (GB15618—95), Juncus Effuses could still grow normally in appearance though its yield decreased by 10%, however biomass of the underground part was not much affected. With the heavy metal concentration increasing, the content of chlorophyll and the ratios of chlorophyll a/b were decreasing rapidly. POD and SOD activities in Juncus Effuses increased first and then decreased afterwards, while CAT activity decreased linearly. In gerneral, the enzyme activities were gradually activated when the concentration of heavy metals was within the lower concentration range of the soil environmental quality which indicated their synergic resistance to heavy metal stress to a certain degree. But the enzyme activities were inhibited when their concentrations got higher. The yield of biomass of the ground part of Juncus Effuses growing on the soil polluted by wastewater or tailings of Lead/Zinc mining decareasd by 28.23% or 37.1% respectively, but the activities of POD, SOD and CAT were all higher than those in CK. All these suggest that Juncus Effuses could be used as an indicator of critical value of the toxic effects of the heavy metals, Cu, Cd, Pb, Zn and As, in soil, set on the basis of the upper limit of Grade II criteria of the State Soil Environmental Quality Standard.