During the vibration measurement of the 61 000 t Bulk Carrier in a sea trial, it was observed that the longitudinal vibration of the accommodation area was very serious with a speed of 91 min/s for the main engine. The reason causing the abnormal structural vibration in accommodation area has been found according to the theory of the finite element modal analysis of the hull structure, combined with the vibration analysis of the local structure and the judgment of the main excitation source. The vibration problem of the accommodation area is then solved by adjusting the ballast water. Finally, the finite element calculation and on the board measurement are carried out for the validation. The calculation and measurement results meet the ISO 6954 vibration standard required by the technical specification. It can provide technical reference for the design and operation of the ship type.