The symptom of vibration caused by bearing fault of two turbine units is analyzed in the paper. It is pointed that the unstable vibration is the typical symptom of this kind of bearing fault. The amplitude of the unsteady vibration is small in early state and become large in later period. There is no relationship between the vibration and load. The case analysis shows that sub-synchronous frequency occurs in the vibration frequency spectrum in case of bearing fault. Shaft vibration is small when bear vibration is big for the two units. It is important to monitor shaft vibration and its trend for the safety and reliability operator of the unit.