Abstract: To realize the rapid construction and aseismic safety of railway piers in complex environments such as mountainous areas, a lightweight segmental precast pier connection structure for high-speed railways in high seismic risk zones was proposed by the basis of the Wenshan-Mengzi Railway bridge engineering project. A refined numerical analysis model for assembled connected piers was established, and the model reliability was verified with existing test results. The influence laws of parameters including socket depth, infilled concrete height, axial compression ratio and segment ratio on the aseismic performance and on the failure mechanism of segmental assembled connected piers were revealed. Based on the pier structure and on the plane section assumption, a calculation model for the flexural bearing capacity of segmental connected railway piers under different failure modes was proposed. The research results show that reducing the socket depth changes the conventional failure mode of such piers, with the reasonable socket depth being 325 mm (0.45D₀). The axial compression ratio is positively correlated with the bearing capacity, and increasing the axial compression ratio mitigates damage to the upper segment. The peak bearing capacity of piers increases with the rise of infilled concrete height within a reasonable range, while an excessively high infilled concrete height elevates the plastic hinge zone at the pier bottom. Different segment ratios affect the pier bearing capacity, and the bearing capacity decreases significantly when the segment ratio is 1:1. The calculations of flexural bearing capacity based on simulation results indicate that the peak bearing capacity is determined by the critical section. The error between the proposed calculated bearing capacity and the actual resistance obtained from tests and simulations is less than 5%, which can provide a reference for the bearing capacity design of similar segmental precast railway piers.