To evaluate the effects of dominant plants on controlling heavy metal pollution and the ecological restoration on indigenous zinc smelting slag dump, this study analyzed the effects of two naturally colonized and lushly grown plants (Chenopodium ambrosioides L. and Buddleja davidii Franch.) on the slag dump, basing on unrepaired blank slags. The effects of the two dominant plants on the main nutrient (nitrogen, phosphorus, and organic matter) and the content and occurrence mode of main heavy metals (Cu, Pb, Zn, and Cd) in the different particle size aggregates in rhizosphere and non-rhizosphere were examined. The results showed that the two naturally colonized dominant plants had significant effects on the main nutrient contents in the different size slags of rhizosphere and non-rhizosphere on the dump. Different plants had significantly different contributions to the organic matter in the rhizosphere and non-rhizosphere slags. The nutrient content had higher distribution in the size <1 mm aggregates. In addition to the total nitrogen content in the non-rhizosphere residue of B. davidii Franch. the nutrient content in the medium were wholly higher than in the blank waste slags. The growth of dominant plants significantly affected the content distribution and occurrence mode characteristics of main heavy metals (Cu, Pb, Zn, and Cd) in different size slags. Cu and Cd were mainly distributed in aggregates with sizes <0.25, 0.25~0.5 and 0.5~1 mm. Zn was mainly distributed in aggregates with sizes <0.25 and 2~5 mm. Pb had the highest content in four different aggregates which sizes were from 0.25 to 5 mm. The contents of Cu and Pb were reduced in the aggregates of various size slags, but the Cd content was improved in aggregates with size >5 mm. Among them, the proportion of acid-soluble Cu, Pb, and Zn decreased significantly, but the proportion of residual Zn and acid-soluble Cd increased in the size <5 mm aggregates. Principal component analysis showed that the plants had a high contribution to the nutrient, total Zn, and acid-soluble Cd content of the size <5 mm aggregates, but had little effects on the nutrient at the size >5 mm aggregate in the rhizosphere and non-rhizosphere. In summary, the vigorous growth of the two plants (C. ambrosioides L. and B. davidii Franch.) can effectively improve the nutrient status of lead-zinc smelting slags, and also reduce the potential risks of heavy metals Cu, Pb, and Zn to environmental ecology. Both plants can be used as pioneer-repairing species for lead-zinc smelting slags dump.