Abstract:In order to explore impact of mining activities on operation of soil system in lead-zinc mining area of Danzhai county, Guizhou province, soil of lead-zinc mining area in Xingren town, Danzhai county was taken as research object, and soil surface layers (0~20 cm) of different land use types around rivers in small watersheds were collected. Content of 7 heavy metals Cu, Cd, Pb, Zn, Mn, Hg, As in soil samples was analyzed. Pollution degree and potential ecological risk of heavy metals in different soil layers in the mining area were evaluated through single-factor pollution index method, Nemeiro comprehensive pollution index method, geological accumulation index method, and potential ecological index method. The results show that content of Cu, Cd, Pb, Zn, Mn, Hg and As in 0—10 cm soil is 0.65, 5.13, 1.74, 2.45, 0.59, 5.08, and 0.27 times of the soil background value in Guizhou province. Content of Cu, Cd, Pb, Zn, Mn, Hg, and As in 10—20 cm soil is 0.71, 3.11, 1.18, 2.21, 0.65, 4.88, and 0.21 times of the soil background value in Guizhou province. Different small watersheds and different depths of soil layers have different levels of damage. The evaluation results show that the main polluting heavy metal elements in study area are Cd and Hg, and the soil heavy metals are at a medium or above potential ecological hazard level.