The variation of magnetic state of transformer often causes the violent vibration of the transformer various parts, especially the core. The most obvious magnetic state change of the transformer is usually caused by the DC component. In this paper, one kind of magnetic compensation method is adopted to suppress the DC bias, and the core vibration caused by the transformer magnetic state change is studied in detail. At first, on the basis of measuring the magnetostriction and calculating the vibration displacement of transformer core, the research on the vibration increment created by the DC bias is carried out. Secondly, the transformer core vibration before and after the DC bias suppression is simulated, and the difference of the transformer with a magnetic compensation capacity is analyzed. Finally, based on the VIBXPERT®II FFT data acquisition and signal analyzer, the vibration of measuring points under the different magnetic state and the different measuring point under the same magnetic state are collected. The vibration tendency of each measuring point is given with the variation of the magnetic state. Thus, the vulnerable spot of the core vibration and the basic law of the transformer vibration are obtained, which could provide a basic method for the reducing vibration.