The invention provides a chemical processing method of coal chemical industry recycled circulating cooling water. An agentia is composed of composite scale and corrosion inhibitor which is composed of 9-11 parts of polyepoxysuccinic acid, 18-22 parts of 2-phosphonobutane-1,2,4-tricarboxylic acid, 19-21 parts of methylene phosphonic acid, 25-35 parts of dirt dispersion agent, 1-3 parts of benzotriazole, and 9-18 parts of deionized water. First, adding polyepoxysuccinic acid into the 2-phosphonobutane-1,2,4-tricarboxylic acid, placing the polyepoxysuccinic acid and the 2-phosphonobutane-1,2,4-tricarboxylic acid in a container and evenly mixing, sequentially adding the methylene phosphonic acid, the dirt dispersion agent and the deionized water into the container, then stirring for 25-35 minutes, keeping the temperature at 20-35 DEG C, then adding the benzotriazole, continuously stirring for 30-60 minutes and keeping the temperature at 20-35 DEG C, and then, the composite scale and corrosion inhibitor is obtained. Dosage of the composite scale and corrosion inhibitor is 10mg / L, based on middle warmer strengthening water, total phosphorus of the circulating water is controlled to be 4-7mg / L, and a concentration ratio is controlled to be 5.0-6.0 times. The method further comprises sterilization and algae removing process and optimization of the circulating water.