Hydrogel　coating　was　widely　studied　in　the　field　of　oil/water　separation　due　to　its　underwater　superoleophobic　performance,　which　could　avoid　the　blockage　of　the　separation　membrane　by　oil　effectively,　especially　high　viscosity　crude　oil.　In　this　manuscript,　a　layer　of　ultra-thin　Polyacrylamide-Tannic　(PAAm-TA)　hydrogel　coating　was　coated　on　the　surface　of　PVDF　microfiltration　membrane　by　a　simple　immersion　process,　which　could　endow　it　with　superhydrophilic　and　underwater　superoleophobic　performance.　Due　to　the　outstanding　superhydrophilic　and　ultrathin　hydrogel　coating,　the　obtained　sample　showed　an　ideal　emulsion　separation　efficiency　and　flux,　99.47%　and　1184.3　L/(m2　h　bar)　for　toluene-in-water　emulsion.　Additionally,　the　residual　crude　oil　on　the　membrane　surface　can　be　easily　and　quickly　removed　by　rinsing　with　water.　Attributed　to　a　variety　of　chemical　and　hydrogen　bonding　and　negatively　charged　groups　on　the　tannic　acid　molecules,　the　membranes　possess　good　mechanical　stability　and　electrostatic　adsorption　properties.　The　obtained　PVDF/PAAm-TA　membrane　could　maintain　its　special　wettability　in　a　wide　range　of　chemical　environments,　enabling　it　great　potential　to　be　used　in　complex　water　treatment.　In　summary,　this　study　will　provide　new　insights　into　a　new　idea　and　method　for　the　preparation　of　hydrogel　coated　porous　materials　for　oil/water　separation.