Abstract:Gain enlightenment from the preparation of pH test paperThrough the selected of color reagent , oxidant , corrosion inhibitor and buffer system to identify a simple and effective composition of colour reaction system , Use of color reagents reaction with different concentrations of iron(III)solution to make the standard color Levels.Sprayed the colour system to the surface of the steel substrate to have color reaction , contrast the standard color levels to analyse to the steel extent of corrosion.