Abstract: This experiment adopted new polymer materials——thermoplastic elastmer as the base material for chemical milling of aluminum alloy to prepare protective coating with different kinds of formula and optimized the formula according to analysis of the performance of self-made products and imported products made by USA,including appearance,viscosity,solid content,corrosion resistance,etching ratio,compatibility,adhesive force and peel ability.Experiment proves that the characteristics of new protective coating of chemical milling of aluminum alloy basically approach those of products of the same kind made by the USA.