The invention relates to a method for preparing an antibacterial filter material by utilizing biomass resources, and belongs to the technical field of air purification. The method provided by the invention comprises the following steps: mixing a surfactant, plant fibers and water to obtain mixed slurry; stirring the mixed slurry until the mixed slurry is foamy, thereby obtaining foam fibers; performing vacuum suction filtration on the foam fibers until a water line is not observed by naked eyes; and drying until moisture content is 10wt% or lower. According to the method, the biomass resources such as crop straw and market pulp which are existed in nature in large numbers are taken as main raw materials, and a novel biomass antibacterial filter material is prepared through a normal-temperature low-pressure mechanical stirring method; a raw material source is wide, and the raw materials can be naturally degraded and regenerated; and the preparation method is simple, is not high in equipment requirement, is relatively low in production cost, is good in product filter effect, is strong in bacteriostatic ability, has excellent characteristics of resisting impact and shock, absorbing noises and preventing moisture, insulating, preserving heat and the like, can be used for respirators, air purifiers, filter elements, and has a good market prospect.