The effect of the residue produced by microbial degradation of gangue filled into underground mine on groundwater was studied. Using the coking coal,gangue,mine water from Pingmei Shier mine as studied material,in the case of adding inoculum,the content of metal Mn,Cu,Pb,Zn,Fe,Co,Ni and organic matter in the residue were measured. The results showed that the contents of the heavy metals have different changes with the soaking time increased,the content of organic matter greatly reduced with the soaking time and the proportion of gangue increased.