In view of the high content of SO42-, Cr6+and Cr3+in acid mine drainage (AMD) and low pH, based on microbial immobilization technology, zero-valent iron filings (ZVSI) and corncob are the main matrix components, and sulfate-reducing bacteria (SRB) organically combined to prepare ZVSI-SRB particles for AMD treatment.In order to explore the particle removal mechanism of SO42-, the related kinetic model was used to mathematically fit the single contaminant ion removal process.The results show that the ZVSI-SRB particles are more in line with the first-order reaction kinetics model for the SO42-reduction kinetics.Characterization by related instruments showed that two crystals of FeS appeared in the particles after the reaction, indicating that a series of complex physicochemical and biochemical reactions occurred during the particle reaction.