Corrosion retarding control method for auxiliary machine cooling water system of thermal power plant

The invention relates to the field of cooling water control methods, in particular to a corrosion retarding control method for an auxiliary machine cooling water system of a thermal power plant, which comprises the following steps: according to specific chemical analysis indexes and water temperature monitoring conditions of pH, alkalinity, calcium hardness and total dissolved solids of circulating cooling water, refining correlation coefficients of all index parameters, and calculating a stability index Iw; adding acid into the circulating water to adjust the pH value, and enabling the pH value to be within a set range; and the scaling degree is judged according to the stability index Iw according to a preset standard, a composite slow-release scale inhibitor is added into the circulating cooling water system, the stability indexes Iw and B are jointly regulated and controlled, the stability index Iw is made to be within a first preset range, then the lower limit of the stability index Iw is adjusted to be w