Unsteady vibration occurred in the Ultra high-pressure rotor,high-pressure rotor and low-pressure rotor for a 1000MW ultra-supercritical turbine generator unit of Taizhou power plant during the debugging process seriously affects the safety and stable operation of the unit.On the base of the detailed vibration analysis,we found that rotor-to-stator rub is the main cause of the unsteady vibration of the three rotors.The field dynamic balancing experiment was proceeded,and the starting method of the unit was changed.The unsteady vibration problem was solved.