［Objective］ To improve the chloride ion resistance of concrete structures in harshenvironments and extend their service life.［Methods］Using methyl methacrylate（MMA）and ethyl acrylate（EA）as base monomers，vinyltrimethoxysilane（VTMS）and perfluorooctyl ethyl methacrylate（TEMAc-8） were introduced for synergistic fluorosilicon modification. The monomer ratio was optimized through orthogonal experimental design，and the effects of each component on hydrophobicity，adhesion and structural characteristics of the coating were systematically analyzed. Theprepared coatings were applied to cement mortar surfaces to evaluate their chloride ion penetrationresistance.［Results］The maximum water contact angle of the modified coating reached 110. 6°，with the highest adhesion strength of 3. 42 MPa. The chloride ion penetration in coated mortar specimenswas reduced by 70% compared to uncoated samples.［Conclusion］ The synergistic fluorosilicon modification improved the hydrophobicity and interfacial bonding ability of the acrylic coating，forminga protective system combining surface water resistance and interfacial chemical bonding. This coatingcan effectively reduce the migration rate of chloride ions into cement-based materials，providing afeasible surface protection strategy for delaying concrete deterioration in chloride environments.