Abstract:Applying heavy metals in the surface layer soil of abandoned chromium slag plant as research object, the changes of surface soil microorganisms and physical and chemical properties were comprehensively analyzed to provide theoretical basis for remediation of soils contaminated by heavy metals in karst areas, as well as the relationship between the environmental factors, through high-throughput sequencing technology analysis. The results show that contents of soil organic matter (SOM), total phosphorus (TP), available phosphorus (AP), available nitrogen (AN) and ammonium nitrogen (NH4+-N) are the highest in the downstream and the lowest in the workshop. At the phylum level, Actinobacteria, Proteobacteria, Acidobacteria and Chloroflexi are the dominant species. At class level, Alphaproteobacteria, Actinobacteria, Vicinamibacteria, Thermoleophilia and Chloroflexi are the dominant species. In general, under the combined action of heavy metals and soil environmental factors, microbial abundance is more likely to be affected by soil environmental factors, and TP, nitrate nitrogen (NO3+-N) and most heavy metals are the main driving factors of microbial change. Actinobacteria is similar to most heavy metals and has the strongest tolerance to heavy metals. Metal element Pb has certain selectivity to the growth and reproduction of bacteria, that is, different metal elements have different effects on soil bacteria groups. In conclusion, according to different contaminated and different plant areas, input of nutrient elements and selection of dominant strains should be considered in restoration and treatment of abandoned plant areas in karst areas. This study deepens the understanding of changes and driving factors of heavy metal contaminated soil microorganisms, and provides a theoretical basis for remediation of contaminated soil from waste chromium slag plant.