Abstract: In order to evaluate the effect of aspartic acid−β−cyclodextrin (ACD) on the soil environment, the microbial populations and soil enzyme activities, cadmium and fluorine co−contaminated soil were studied. The number of main microbial populations and the enzyme activities of the soil contaminated with 100 mg·kg⁻¹ fluorine and 15 mg· kg⁻¹ cadmiumin at the presence of ACD were analyzed by plate colony counting and the enzyme assay. The results showed that with 2% ACD being added to the contaminated soil, the activity of urease and polyphenol oxidase increased by 26.85% and 35.40%, respectively, the number of bacteria, fungi and actinomycetes in contaminated soil increased by 43.86 %, 35.40 % and 70.96%, respectively. It could be concluded that ACD has evident accelerating effect on the improvement of enzyme activities and microbial populations in soil, which may improve the soil environment.