[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.