Abstract: In order to upgrade the protection ability of acrylic coating on the surface of cement concrete, graphene were employed as fundamental filler in acrylic coating, and the graphene modified acrylic composite coating was prepared on the surface of cement mortar cubes. The effects of graphene dosage in the polyacrylic coating and water-cement ratio in the preparing process of cement mortar samples on the MgSO₄ corrosion resistance of the samples were investigated, and the composition design of protective coating was optimized. The results show that the mass increment ratio and the strength loss ratio of the cement mortar samples due to the corrosion of MgSO₄ solution reduced evidently with the increase of graphene dosage in the coating. However, the excessive amount of graphene caused the mass increment ratio and the stength loss ratio of the coating to rise. A graphene dosage of 0.4% (mass fraction) was proposed as optimal value, which showed good improvement on the MgSO₄ corrosion resistance of the samples with different water-cement ratios. The lower water-cement ratio (0.4) was conducive to the formation of cement mortar samples, and improve their MgSO₄ corrosion resistance.