The finite element software ANSYS is used to construct a model of large vertical ship lift,which includes tower column,ship chamber,water,ship,lifting system and so on.The dynamic characteristics of the ship lift structure are calculated and analyzed.The results show that the lateral swing,the torsion and the longitudinal swing are the main vibration modes of the ship chamber.A ship in the ship chamber will reduce the natural frequency of the system.The frequencies of the lateral swing under the condition with and without ship are 0.130 9 Hz and 0.280 5 Hz respectively.The low-order vibration mode of the whole structure of ship lifter mainly includes the transverse vibration of the whole system,the vertical torsion of the whole system and the longitudinal vibration.Whether there are ships in the chamber,the difference in natural frequency calculated of the whole system is small which shows that ship has little influence on it.The natural frequency value of the ship lift is decreasing with the increase of the position of the ship chamber.The position change has a great influence on the low-order vibration modes of the ship lift and has little influence on the high-order vibration modes.