The paper f irst analyses the theory and the effect of the TRASAR control technique which is used in Shanghai Baoshan Steel & Iron Group 1420 Cold Rolling Mill circulat ing cooling water and the water stabilizing system.Auther compares the TRASAR controlling solution with the traditional one.Comparing the chemical dosing method in water treatment with the traditional,the writer set forth deeply the applicat ion field,the character and the future of the TRASAR control technique,which is the patent of Nalco,USA.