Sodium benzotriazole can be absorbed on the 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 sodium benzotriazole has good corrosion inhibition effect in circulating cool water system. The dosage of 2-4 mg/L is preferred. Sodium benzotriazole can also be used as an anti-discolor agent, coating additive, and lube oil additive.