Under the dynamic load of high-speed railway trains, the tunnel structure is easily damaged when it passes through the transition section of hard-soft rock, while the dynamic research and related vibration reduction measures of such kind of engineering are rarely involved yet. Therefore, based on the engineering case of Xiangsishan Tunnel project of Guangzhou-Zhanjiang Railway, numerical calculation method was adopted to compare and analyze the dynamic response characteristics of the tunnel structure passing through the hard-rock transition section without reinforcement and with different pile-plate reinforcement. The research results show that under the action of train load, the acceleration, dynamic displacement and dynamic stress response of the tunnel structure located around the interface of soft rock are very different from that of the hard rock, resulting in poor transition effect near the tunnel interface, which is not conducive to the stability of the structure. After the reinforcement of three different pile-plate structures, the dynamic response of the tunnel structure in the soft rock side decreases and is closer to the dynamic response of the tunnel structure in the hard rock section, and the transition effect is very significant. In contrast, pile-plate structure 1 (namely, bearing plate + supporting plate + bored pile) has the best damping and transition effect.