A metal organic frame reverse osmosis membrane and a preparation method therefor. A support layer of said reverse osmosis membrane is synthesized from a polymer and an active hydrophilic stabilizer. A desalting layer on the support layer is a functional layer which has a cross-linked nanocrystal network structure and is formed by subjecting the support layer to an interfacial polymerization reaction of an aqueous phase solution and an oil phase solution. The preparation method for said reverse osmosis membrane comprises preparation of a polymer support layer, preparation of a metal organic framework nano ion, and preparation of a desalting layer. The presence of the metal organic framework provides a large number of hydrogen bonds to the functional layer, and at the same time, the metal organic framework can crosslink and condensate with free amino groups in the functional layer, thereby increasing the degree of crosslinking of the reverse osmosis membrane. The reverse osmosis membrane has a small film thickness, greatly saving manufacturing costs. More importantly, the reverse osmosis membrane can greatly increase the membrane flux without affecting the salt removing rate so that the operating energy consumption of the membrane is reduced, and thus is a low-energy consumption seawater desalting membrane having superior properties.