Abstract: The present disclosure relates to a nanofiltration membrane preparation method, and a nanofiltration membrane prepared thereby. The preparation method comprises the following steps: preparing a casting solution, and curing the casting solution on a reinforcement material to form a base membrane; sequentially contacting the base membrane with a water phase solution and an oil phase solution so as to perform an interfacial polymerization reaction on the base membrane to form a polyamide functional layer, wherein the water phase solution includes a water phase monomer and an additive, the additive is a glycosylated sulfonamide compound, and the oil phase solution includes an oil phase monomer; and performing post-treatment to obtain a nanofiltration membrane, the post-treatment comprising hydroxylation treatment and crosslinking treatment.