The　safety　and　long-term　stability　of　tunnel　engineering　rely　heavily　on　the　lining　construction　time,　primarily　determined　through　in-situ　monitoring　of　the　stability　of　the　surrounding　rock.　However,　this　approach　needs　a　rational　theoretical　basis.　To　address　this　issue,　a　method　that　uses　displacement　back　analysis　technology　is　proposed　for　a　new　railway　tunnel　project.　This　method　considers　the　constraint　effect　of　the　lining　on　the　surrounding　rock　and　primary　support.　It　involves　fitting　a　deformation　curve　based　on　primary　support　monitoring　data　to　determine　the　residual　deformation.　The　corresponding　surrounding　rock　stress　field　is　derived　using　displacement　back　analysis.　This　stress　field　is　then　applied　to　the　primary　support　and　lining　via　the　finite　element　method　to　obtain　the　lining　stress.　Evaluation　criteria,　such　as　allowable　tensile　stress　and　shear　safety　factor,　comprehensively　assess　lining　safety　and　determine　its　earliest　construction　time.　The　results　show　that　the　residual　deformation　of　the　primary　support　decreases　gradually　over　time,　with　a　substantial　deceleration　rate　within　the　first　10　days　after　primary　support　completion.　The　earliest　lining　construction　time　for　a　specific　tunnel　case　is　39　days　after　primary　support　completion.　At　the　in-situ　lining　construction　time　(100　days　after　primary　support　completion),　the　monitoring　results　of　the　lining　internal　force　align　well　with　the　back　analysis　results,　confirming　the　feasibility　of　the　proposed　method.　©　2023　Editorial　Office　of　Chinese　Journal　of　Plant　Ecology.　All　rights　reserved.