To address the high labor intensity and low construction efficiency associated with railway tunnel lining reinforcement, a prefabricated composite lining structure primarily composed of ultra-high performance concrete (UHPC) with novel socket-spigot joints is proposed. This structure allows rapid assembly and is applicable to double-track high-speed railway tunnels. Through laboratory tests, numerical simulations, and field experiments, the mix proportion of casting materials is optimized, the mechanical characteristics of the lining under varying surrounding rock loads are analyzed, and the segmentation configuration, circumferential and longitudinal joint connection types, and joint arrangement scheme for prefabricated blocks are determined, culminating in a complete construction technology for lining installation. The main findings are as follows: (1) For a double-track high-speed railway tunnel section designed for 350 km/h, dividing the full ring into six standard segments and one adjustable segment minimizes the variety of prefabricated components while satisfying staggered joint assembly requirements. (2) The optimized mix proportion ensures adequate UHPC mechanical performance with a final setting time of 368 min. (3) A UHPC lining thickness of 150 mm yields a safety factor of eight or higher at all monitored locations under grade Ⅲ, Ⅳ, and Ⅴ surrounding rock conditions, confirming excellent structural performance. (4) Joints pre-embedded with short insertion travel enable efficient segment-to-segment assembly through pushing from a construction trolley. (5) Employing a self-developed lining assembly vehicle and a bottom-to-top, piece-by-piece installation process, lining construction within maintenance windows is feasible.