[Objective] The effects of mixed additions of a water-retaining agent and bacterial agents on soil characteristics were determined in order to provide a theoretical basis for promoting mine vegetation restoration. [Methods] Different concentrations of a water-retaining agent and mineral-solubilizing microbial agents were added to the potted soil of Robinia pseudoacacia. The concentrations of the water-retaining agent were: B1 (0%), B2 (0.3%), and B3 (0.5%). The microbial-agent treatments were J0 (without added microorganisms), J1 〔adding NL11(Bacillus thuringiensis)〕, J2 〔adding NL11 + NL11(Streptomyces thermocarboxydus)〕, J3 〔adding NL11+NL1+NL15(Gongronella butleri)〕. The effects of mixed additions of the water-retaining agent and microorganisms on R. pseudoacacia were determined by analyzing the growth, soil nutrients, soil organic carbon, and soil enzyme activity of R. pseudoacacia. [Results] ① The addition of microbial strains increased soil nutrient content and soil enzyme activity. The J2 microorganism treatment performed the best. ② Readily available soil nutrients initially increased and then decreased with increasing concentration of the water-retaining agent. The greatest effect on soil nutrient and enzyme activity was observed for the 0.3% water-retaining agent concentration. ③ The combinations of J2B1, J3B0, and J2B2 had the greatest effect on increasing soil nutrients and enzyme activities. [Conclusion] The addition of soil microbial agents and a water-retaining agent to the soil increased soil nutrients and enzyme activities. The combinations of J2B1, J3B0, and J2B2 had the greatest effect
