BTA•Na can be absorbed on metal surface and form a thin film to protect copper and other metals. BTA•Na can be used together with many scale inhibitors and fungi disinfectants in circulating cool water system, and it has good corrosion inhibition effect in circulating cool water system. The dosage of 2-4mg/l is preferred. BTA•Na can also be used as anti-discolor agent, coating additive and luboil additive.