Ultralow-use-concentration antirust powder used in circulating water

The invention relates to ultralow-use-concentration antirust powder used in circulating water. The cleaning agent is prepared from the following raw materials in percentage by mass: 40-70% of sodium tetraborate, 5-25% of sodium hydroxide, 5-15% of dodecanedioic acid and 5-30% of aza-benzene ring polyaminocaproic acid. The rust-proof powder is high in cost performance, can ensure that the inner wall of a circulating water pipeline and other metal components are not corroded within one month under the 0.1% ultralow concentration, is suitable for cast iron, steel, stainless steel and other metals, is also suitable for cast iron, steel and other structural members plated with nickel and chromium on the surface layers, and is not suitable for coatings or structural members containing active nonferrous metals such as aluminum and zinc. The use method comprises the following steps: firstly, running water passes through the water treatment filtering system, the water quality standard meets the chemical industry water