Water supplementing method and device for open-circuit circulating water system

The invention relates to a water replenishing method and device for an open-circuit circulating water system. The method comprises the steps of: monitoring N water quality characteristics of circulating water; calculating an instant water replenishing coefficient, and obtaining a stable value of the water replenishing coefficient; and calculating the ratio of the instant water replenishing coefficient to the stable value of the water replenishing coefficient, and if the ratio is lower than a set threshold value, carrying out water quality standard exceeding early warning. According to the method, the stable state of the water system is described by adopting the long-term stability coefficient, and the adaptability is better along with data accumulation and updating in continuously adapting to slow changes in various aspects of the water system. The sudden change state of the water system is pre-warned based on the relative balance coefficient, influences of objective factors such as water mixing, instrument e