Abstract: In order to solve the problems of superficial ecological deterioration and decline of water resources in the ecologically fragile mining area caused by the downward cracks in seam mining, the unconfined compressive strength test and direct shear test were used to determine the changes of physico-mechanical properties of the reinforced sample with microbial solution of different concentrations, and reveal its mechanism. The results show that with the increase of the concentration of the microbial bacteria liquid, the unconfined compressive strength and shear strength of the sample are gradually increased, and the ability of the bacteria liquid to repair the fractured soil becomes enhanced, which can improve the physico-mechanical properties of the soil to a certain extent.