An energy-saving and water-saving device for distributed control over industrial circulating water comprises an operating system, a central computing control system, a PID control system, an on-site execution system I, an on-site execution system II and an on-site instrument system. Detection instruments of the on-site instrument system are distributed at corresponding detection sites in pipelines and circuits of a soft water closed circulation system and corresponding detection sites in pipelines and circuits of a purified water circulation system. In a method for achieving distributed control over the industrial circulating water through the device, based on the principle of centralized management and distributed control, the central computing control system issues an execution instruction to the on-site execution system I and the on-site execution system II according to parameters set by the operating system, meanwhile constantly carries out computation, analysis and comparison on data fed back by the on-site instrument system and the on-site execution system II and a set value, and gives an adjustment and correction instruction so as to guarantee normal operation of the water circulation systems and achieve efficient integration of industrialization and informationalization. The device is completely intelligent, high in automation degree, easy and convenient to operate, efficient, safe, reliable and low in environmental pollution and saves energy and water.