Abstract: The synthesis technology of one pack polyurethane coating by substituting phthalic anhydride for part of TDI is discussed in this paper. The influence of variables such as the kind of oil, oil length, the quantum of TDI and solvent, and the temperature of synthesis on property of polyurethane coating is investigated. By introducing some improved epoxy resin to the synthesised polyurethane, a kind of coating for various substrates with good performances is developed.