The invention discloses a single-track railway tunnel full cross-section excavation rack. The single-track railway tunnel full cross-section excavation rack includes bottom beams, stand columns, lateral fixing platforms, lateral extensible sleeve pipes, upper part working platforms, middle part working platforms, front part extensible sleeve pipes, middle part turnover working platforms, upper door beams, lower door beams, a crawling ladder, and an escaping rod, wherein the stand columns are mounted on the upper parts of the bottom beams, an door-shaped integral structure is formed by the stand columns, the upper door beams and the lower door beams, the lateral working platforms are mounted on the laterals of the stand columns, the upper part working platforms are mounted on the upper doorbeams, and the middle part working platforms are mounted on the lower door beams; the front extensible sleeve pipes are mounted on the lower door beams and the lateral working platform; the middle part turnover working platforms are mounted inside the stand columns; the crawling ladder is mounted on the rack, and the escaping rod is mounted between the upper part working platform and the ground;and guardrails are mounted on the upper part working platforms, people can be prevented from falling, and safety of working personnel is ensured. The single-track railway tunnel full cross-section excavation rack is reasonable in structure, humanized in design, high in fracture surface applicability, and good in safety protection measure, and the maximum operating space for other processes of tunnel excavation is ensured.