The present invention provides a hydrophilic/oleophobic sponge, a preparation method and use thereof, and belongs to the technical field of functional material preparation. In the present invention, a modified solution is obtained by mixing a nanoparticle suspension with a modifier solution; the nanoparticle suspension includes silica-encapsulated Fe3O4 nanoparticle suspension and/or nano-silica ethanol suspension; the modifier solution includes chitosan-acetic acid aqueous solution and polyvinyl alcohol (PVA) aqueous solution. The sponge is soaked in the modified solution, mixed and crosslinked with glutaraldehyde aqueous solution to obtain the hydrophilic/oleophobic sponge, conferring good oil-water separation ability on the sponge. The sponge effectively separates a heavy water layer from oil-water mixtures with such light oils as lubricating oil, engine oil, pump oil, crude oil, gasoline, and sunflower seed oil in a simple gravity-driven manner. The hydrophilic/oleophobic sponge prepared by the present invention has good application prospects in oil-water separation.