The invention discloses a super-hydrophilic/underwater super-oleophobic oil-water separation metal mesh membrane and a preparation method thereof, wherein a functional coating is constructed on the surface of a metal mesh membrane through biomimetic adhesion chemistry, and then a modified metal mesh membrane for oil-water separation is prepared by using a thiol-terminated hydrophilic polymer as afunctional modification reagent through a Michael addition reaction. According to the present invention, the used thiol-terminated hydrophilic polymer is prepared through RAFT polymerization, and thechemical structure of the modification agent can be controlled; the prepared modified metal mesh membrane has characteristics of super-hydrophilicity, underwater super-oleophobicity, oil adhesion resistance, stable structure performance and reusability, can efficiently separate the mixed solution of n-hexane, petroleum ether, toluene, gasoline, diesel oil, edible oil, crude oil and water, and hasgood application prospect in the fields of oil recycling and energy saving and emission reducing; and the modification method is simple and has universality, the structure of the modification agent iscontrollable, and the method is suitable for industrialization.