Abstract: For current status that cooling water system of evaporative condenser uses manual control in mine construction utilizing freezing method, an automatic energy-saving control system of cooling water of evaporative condenser was designed in order to simplify process and improve efficiency. In the system, cooling water level of evaporative condenser is converted into electrical signal by use of ball float level controller for controlling circulating pump through contactors, intermediate relays and other low-voltage electrical apparatus, so as to realize automatic circulation of cooling water of evaporative condenser. Cooling tower in total water storage tank and operation mode of the system are controlled by use of temperature controller through detecting temperature of cooling water, so as to ensure safe, high-efficient and energy-saving operation of refrigeration system in construction utilizing freezing method.