Abstract: The damage problem of shield tunnel-segments during the operation of a shield tunnel is becoming increasingly serious in the world. Thusly, a new method is proposed to reinforce the tunnel lining based on the ultra-high-performance concrete (UHPC) which has high performance in the mechanical properties and durability. A three-dimensional nonlinear finite element model for reinforcing the shield tunnel with UHPC is established. This method discusses the mechanical properties and deformation behavior of structures and reveals the bearing mechanism and failure mode of the reinforcement with UHPC. Subsequently, the influence of different thickness and reinforcement ratio of UHPC reinforcement layer on the structural reinforcement is investigated. The simulation results indicate that this new method for reinforcing the shield tunnel with UHPC can effectively control the deformation of the segment and enhance the bearing capacity of the structure. Furthermore, the allowable value of the further development of the relative displacement between top and bottom can reach centimeter level under the condition of satisfying the crack resistance. This research results provide a basis for further research and development of this new method.