Marine structures, such as ship hulls and offshore platforms, are basic elements in marine engineering. Due to the harsh ocean environment, marine structures are prone to adhesion and corrosion by marine biofouling. The biomimetic antifouling technology has been recognized as the most promising solution to marine biofouling, while there is still a long way to go to take this technology outside of research laboratories. In order to develop practical biomimetic antifouling techniques, this work presents a new water jet-based biomimetic antifouling model for marine structures to prevent the enrichment of biofouling. First, a semi-empirical formula is proposed based on the Schlichting self-similar solution to determine the effective width of the water jet. Then, a numerical simulation model is established to investigate the effects of the jet parameters (such as the jet aperture, jet velocity, and jet hole spacing) on the water jet distribution. Subsequently, visualization experiments are carried out to compare and validate the numerical simulation results. Finally, the simulation data are used to train a genetic neural network to predict the effective jet coverage ratio. The optimal parameters of the antifouling model are obtained corresponding to the largest effective jet coverage ratio. The findings of this study deliver a practical biomimetic antifouling technique for marine structures.