［Objective］ This study aims to develop a polyurethane-based marine antifoulingcoating combining fast curing characteristics with environmental friendliness.［Methods］ A UV-curable sulfobetaine-type zwitterionic castor oil-based polyurethane resin was prepared by using azwitterionic precursor synthesized via thiol-ene addition reaction，isophorone diisocyanate，castor oil， hydroxyethyl acrylate and 1，3-propanesultone. The antifouling coating was obtained through UVcuring. The precursor structure was characterized by FT-IR， ¹H NMR and HRMS，and the conversion rate of carbon-carbon double bonds in the resin was determined. The water absorption，water contact angle，diatom adhesion resistance and biotoxicity of the coating were systematically investigated.［Results］With the increasing of zwitterionic content，the water absorption rate increased significantly， the coating water contact angle decreased，and the diatom attachment density on the coating surfacedecreased. The coating with 30% zwitterionic precursor exhibited the lowest diatom attachment density of（68±26）cells/mm². Moreover，the coating showed no toxic effect on diatom growth.［Conclusion］ The zwitterionic coating can effectively inhibit the attachment of Nitzschia closterium，and has no significant effect on diatom growth.