Abstract: Metal sulfide open-pit mines are the main types of metal mines in China.Many acid slopes remained in mines have not been comprehensively treated since mining.Sulfide in the exposed slope reacts with air and rain to form acid water, and then leach heavy metal elements from ore body or surrounding rock to pollute the environment; simple green planting is not suitable.This paper analyzes the pollution mechanism of acid slope, and determines the way of pollution migration.In order to control the oxidation of sulfide in the slope and the generation of acid water from the source, the technology of isolation, sealing, in-situ solidification and thick layer spraying was used to comprehensively treat the acid slope.The formula of isolation base material and thick layer spraying base material is adjusted to form a solidified isolation layer and a green vegetation layer on the slope surface.Through the application of typical metal sulfide mine slope treatment project, the heavy metal elements and pH value in the slope erosion water samples after treatment are far lower than those before treatment, and reach the class V water standard in the environmental quality standard for surface water.It is proved that the in-situ solidification technology and thick base material spraying technology can control the oxidation of metal sulfide in acid slope, which provides a certain reference for the comprehensive treatment of similar mine slope.