A lightweight modified filter material, a preparation method therefor and use thereof, the lightweight modified filter material being prepared from the following components in parts by mass: 75-100 parts of waste glass, 5-20 parts of a metal oxide modifier and 1-10 parts of a foamer. The lightweight modified filter material has the advantages of being lightweight, having large specific surface area, a high isoelectric point, porosity and the like, increasing the isoelectric point and service life of the filter material. The added metal oxide can be combined with SiO2 in the glass to form Si—O-Me (Me metal ions) and enter the glass network.