Abstract: The dynamic characteristics and the random seismic response of Three Gorges’ ship-lifting tower structure were investigated by using 3-D FEM model. The dynamic characteristics results show that the tower structure has large flexibility. The random seismic response is found to be a median-wide band process. Based on the first excursion probability mechanism, the time dependent dynamic reliability of the ship-lifting tower structure under designed earthquake intensity was calculated by assuming the reliability level to be the displacement limit of the structural typical position on the top floor of the tower. The time dependent dynamic reliability of the tower structure in the design base period was obtained. The effects of the definite level and the random level on the time dependent dynamic reliability under a seismic load were also discussed. The model based on Markov hypothesis is advised for aseismic reliability analysis of ship-lifting tower structures. It could provide engineering information for the design and safe service of ship-lifting structures.