Abstract: According to the vibration fault characteristics of the two-stage axial adjustable induced draft fan with movable blades, the shafting support and dynamic characteristics are analyzed, and the bearing incremental force under different types of imbalance is analyzed. Thus, the vibration reduction method of on-site biplane dynamic balance of this kind of fan is proposed, the rotor vibration treatment strategy is expanded, and the flow chart of comprehensive treatment for vibration fault is compiled. The above method is applied to the vibration treatment of a single row induced draft fan of a 660 MW unit, which achieves accurate dynamic balance and significantly reduces the vibration.