Soft water closed circulating cooling water system has been widely used in blast fur-nace,electric furnace steelmaking and other processes.Combined with the example of the 50t spe-cial alloy smelting water treatment project,the electric furnace steelmaking soft water closed cooling water system was discussed,the system's design parameters,equipment selection and design tech-nology improvement were introduced in detail,and the system's application prospects were analyzed as well.