The invention relates to a modified polyurethane asphalt corrosion-resistant coating. In the adopted technical scheme, the corrosion-resistant coating is prepared by mixing a component A and a component B in weight ratio of 1:0.5-1.5, wherein polymethylene polyphenyl isocyanate, isophorone diisocyanate, acrylate, polyether 3031K, polyether 450, dioctyl ester, epoxy resin, phosphate, solvent No.S1000 or industrial xylene are put into a reaction kettle, and react for 0.5 hour at the temperature of 40-42 DEG C, the temperature is raised to 80-82 DEG C, the heat is preserved for 2 hours, the temperature is decreased, and then the component A is prepared; and petroleum asphalt, coal tar asphalt, cyclohexanone, toluene, solvent No.S1000 or industrial xylene and epoxy rein are put into the reaction kettle, the heat is preserved for 2 hours at the temperature of 135-140 DEG C, and the temperature is decreased to room temperature; then, aluminum triphosphate, strontium chromate, mica powder and glass flake are added, grounded, and dispersed, and then the component B is prepared. The coating adopting the invention has the advantages of strong adhesive force, no moisture permeation, strong corrosion resistance, and long service life.