The invention provides a self-polishing antifouling resin and a preparing method thereof. The self-polishing antifouling resin is prepared from, by weight, 10-44 parts of a bifunctional zinc acrylate monomer solution, 55-70 parts of other acrylate polymerizable unsaturated monomers, 0.8-5 parts of an initiating agent and 40-55 parts of a mixed solvent. The self-polishing antifouling resin comprises the bifunctional zinc acrylate monomers and other free-radical-initiated-polymerization unsaturated monomers, and the mixture is prepared into a matrix resin component in an antifouling coating for an environment-friendly ship through copolymerization. According to the self-polishing antifouling resin and the preparing method thereof, synthesized cross-linking-type zinc acrylate resin serves as the antifouling coating of a main film-forming substance, and has the good base-material adhesive force, the certain self-polishing rate, the good antifouling effect in the ocean environment and good practical applications and development prospects.