The invention discloses a bicomponent polyurethane waterproof paint, which consists of a component A and a component B in weight portion, wherein the component A consists of 60 to 70 portions of toluene di-isocyanate(TDI), 7 to 10 portions of polyether N-330, 16.8 to 30.9 polyether N-220, 2 to 3 portions of amine-terminated polyether resin and 0.1 to 0.2 portion of stabilizing agent tartaric acid; and the component B consists of 20 to 30 portions of polyether N-330, 0.5 to 1 portion of antioxidant, 3 to 5 portions of tinting color, 4 to 8 portions of vulcanizing agent MOCA, 10 to 20 portions of vacuum distillate 4 line oil, 8 to 20 portions of chlorcosane, 4 to 8 portions of plasticizing agent DOP and 15 to 20 portions of sericite in powder. The invention also discloses a preparation method for the paint. The bicomponent polyurethane waterproof paint has the advantages of high solid content, high strength, and high elongation at break, and is especially suitable to be used as a waterproof layer of concrete bridge decks of high-speed railways, highways, lines for passenger transportation and lines for both passenger and freight transportation.