Abstract: A HPLC method for determination of benzotriazole (BTA) and its application to the analysis of circulating cooling water sample was proposed. The Kromasil C18 chromatographic column (4.6 mm×250 mm, 5 μm) was used for the separation, and a mixture of acetonitrile and water (25+75) was used as mobile phase with flow-rate of 1.0 mL·min-1. UV-detection at 260 nm was adopted. Linear relationship between values of peak area and mass concentration of benzotriazole was obtained in the range of 3.84 to 76.8 mg·L-1. Test for recovery was made by adding standard BTA to a known BTA sample and analyzing by the proposed method, result of average recovery (n=5) found was 96.4%.