Having excellent weather resistance, corrosion resistance and alkali resistance hot galvanized steel and preparation method and the surface treatment agent

The present invention discloses a method having excellent weather resistance, corrosion resistance and alkali resistance of galvanized steel and environmentally friendly thermal surface treatment agent by using a specific solvent-free aqueous aliphatic polyurethane dispersion and aqueous polyurethane - acrylic acid copolymer environmentally friendly aqueous surface treating agent complex thereof as a matrix resin, silicone-based compound, a matrix resin curing agent, a water-soluble metal salt compound and high density polyethylenes and other ingredients to aid lubrication of galvalume steel sheet galvalume steel sheet after surface treatment process is formed, having excellent weather resistance overall performance, corrosion resistance and alkali resistance and good moldability and the like.