［Objective］To solve the problem of marine biofouling on fishing nets during their use.［Methods］ A polyurethane resin with both degradability and self-generation of zwitterions wasprepared by using bio-based polylactic acid（PLA）as the soft segment，isophorone diisocyanate（IPDI） as the hard segment，and then extending the chain with poly（carboxybetaine）ester diol（PCB）and 1，4-butanediol. The number-average molecular weight and glass transition temperature of resin were characterized. Furthermore，the coating’s flexibility，adhesion strength，contact angle，hydrolytic degradation rate，and antifouling performance on fishing nets in a marine environment were investigated.［Results］When the PCB content is up to 20%，the polyurethane coating has good flexibility and adhesion to polyethylene（PE） substrate，and can self-generate zwitterions in seawater，forming self-renewingsurface through hydrolysis and degradation. The PE fishing nets coated with such coating show obviousantifouling performance after immersion in the sea for 3 months.［Conclusion］The above work providesnew ideas and references for the development of antifouling coatings applied in marine aquaculture.