[en] The purpose of the auxiliary steam supply system is to provide auxiliary steam for users when the main steam is not available. This paper develops a targeted optimization solution through analyzing the influence factors of internal corrosion rate during the operation of the auxiliary boiler. Wet maintenance is carried out by using hydrazine and ammonia water mixture during the shutdown of auxiliary boiler, without changing the existing structure and equipment of the auxiliary boiler. In addition, an appropriate amount of hydrazine is added to the feed water of the auxiliary boiler during the operation of the auxiliary boiler, so as to effectively reduce the content of corrosion products in the water of the auxiliary boiler during its operation, and guarantee the safe operation of the auxiliary boiler. (authors)