Water-control feeding method and system for industrial circulating water

The invention discloses a water-control feeding method and system for industrial circulating water. The position of a buffer tank is lower than the position of a reagent storage tank; the reagent storage tank communicates with the buffer tank through a pipeline; the communicating pipeline is provided with a mixer and a second metering valve; the mixer is further connected with a first metering valve, so that under a siphon effect generated by the pipeline where the mixer is positioned when water is supplemented in the buffer tank and under the gravity of a reagent, the opening degrees of the first metering valve and the second metering valve are regulated, so that a diluted water treatment agent in the reagent storage tank is diluted online by the process that supplementing water is introduced into the mixer according to a proportion by opening the metering valves, and then the diluted water treatment agent flows into the buffer tank. The method has the advantages that continuous powercan be provided by negat