The invention relates to a formula of a coating solution and a preparation method and application of the coating solution. The coating solution comprises the following raw material ingredients: graphene, polyurethane resin and water, wherein the mass ratio of the graphene to the polyurethane resin to the water is (0.18 to 0.23): 100: (50 to 80). A specific application method comprises the step of coating leather-based fabrics with the coating solution, wherein the leather-based fabrics comprise one or more of knitted fabrics, woven fabrics, non-woven fabrics, ultra-fiber non-woven fabrics and true skin. By adopting the technical scheme provided by the invention, the graphene is compounded into a coating material, so that prepared leather products, particularly leather summer-sleeping mats have excellent functions such as wear resistance, scratch resistance, electrostatic resistance, wave absorbing, bacterial resistance, mildew proofing, UV aging resistance, flame retarding, smoke suppressing, electromagnetic shielding and far-infrared health care; the grade of leather can be comprehensively improved, and the performance of cowhide summer sleeping mats in our country in the aspects of comfortability, durability and mildew proofing and bacterial resistance is improved.