HEDP.Na2 is an organophosphonic acid corrosion inhibitor, it can chelate with Fe, Cu, and Zn ions, it can dissolve the oxidized materials, it has good scale and corrosion inhibition effects even under 250�ºC,it is stable under high pH value, not easy to be hydrolyzed, not easy to be decomposed under normal light and heat condition, its acid/alkaline and chloride oxidation tolerance are better than that of other organophosph- onic acids. HEDP.Na2 can form six-ring chelating compounds with metal ions in water system, Ca2+ in particular. HEDP.Na2 has good scale inhibition effects and obvious dissolution threshold effects. When usedwith other Water Treatment Chemicals, the synergistic effects is better. Application scope and method of use HEDP.Na2 is widely used in circulating cool water system, medium and low-pressure boiler, oil field water pipelines as scale and corrosion inhibitor in fields such as electric power, chemical industry, metallurgy, fertilizer, etc. In light woven industry, HEDP.Na2 is used as detergent for metal and nonmetal. In dyeing industry. The dyes the industry fixing agent in non-cyanide electroplating used as chelating agent.