The situation of adopting pressurereducing method without flameout to blow tubes in commission debugging of boilers for homemade 2×600 MW supercritical units in the first project period of Huaneng Qinbei Power Plant has been presented. The practice proved that the adoption of said method makes the hydrodynamic performance in waterwall to be stable

and the tube wall of waterwall

superheater

and reheater to be not overtemperature

and the operating complexity of operators to be greatly simplified. The successful appication of said method can provide reference for steam blowing of oncethrough boilers with similar waterwall structure and similar startup system.