Abstract: Through finite element model calculation, the way the length and depth of cracks in railway tunnel lining impact structural safety has been analyzed, and structural safety sensitivity analysis has been conducted through the orthogonal test. On this basis, the comprehensive evaluation model for impact of lining cracks has been established that is based on the 3 characteristic parameters including length, width and depth (ratio), thus it is possible to conduct quantitative evaluation of how longitudinal crack defect of single-track railway tunnel lining impacts lining structure safety and to create the reference table for normative evaluation.