Abstract: With the volcanic rocks filter material as the carriers, hydrated manganese dioxide modified filter material was prepared to the iron and manganese ion r emoval from the mine water.When the filtration speed was 7.0 m/h and during a continued 54 h filtration period, the manganese ion removal rate with modified volcanic rocks would be 94.8%99.3%.The X-ray diffraction, scanning electron microscopy-energy spectrum and other means combined verified that after the volcanic rocks modif ied, a hydrated manganese dioxide layer covered on the surface of the modified volcanic rocks would have rich surface hydroxyl (- -Mn一_OH) .According to the surface f itting mode, H in hydroxy| could have a surface complexation reaction with Mn2+ and Fe2+ in mine water, finally Mn2+ and Fe2+ could be absorbed by surface hydroxyl and the hydrogen could be replaced.Therefore, the removal of the iron and manganese ion could be realized.