In view of the situation that most of the reagents added to the present circulating cooling water systems are scaling and corrosion inhibitors. The main reasons which effect the heat exchange efficiency and the length of heat exchange equipment lifetime are corrosion and scaling. An on line monitor technique based on electrochemical measuring principle and chemical engineer heat transfer principle is studied and prepared, to inspect the corrosion speed and do the scaling heat resistance real time control for industrial circulating cooling water systems. The technique has the following superiority in 3 aspects:(1)In the corrosion speed measurement by stable electrochemical at certain flow speed;(2)In the comprehensive evaluation on corrosion and scaling;(3)It the has a powerful, visible data process software and a real time computer monitoring function. The practice at TPCC shows the monitor results have good effect on keeping informed on the running state of the equipment on time, and, furthermore, directing the production.