To　evaluate　the　structural　safety　of　the　long-span　pre-stressed　truss　shell　structure　during　the　tensioning　process　of　the　cable　construction　and　determine　the　optimal　and　reasonable　construction　tensioning　scheme,　the　prestressed　truss　shell　structure　system　of　Peking　University　Gymnasium　was　taken　as　the　research　object　in　this　study.　Finite　element　analysis　tool　ANSYS　was　adopted,　and　the　construction　process　reverse　analysis　method　with　‘state　determination’　and　the　element　death　and　birth　technology　were　employed　to　carry　out　the　optimization　analysis　on　the　roof　structure　of　Peking　University　Gymnasium.　The　impacts　of　construction　and　stretching　sequence　and　stretching　series　on　structural　deformation　and　member　stress　were　investigated,　and　the　forming　process　of　the　geometrical　mechanical　system　of　structure　was　monitored.　Finally,　the　optimal　stretching　scheme　was　determined.　Besides,　four　load　cases　and　thirteen　load　combinations　were　considered　to　evaluate　the　safety　of　structure　during　construction　process.　Analysis　results　show　that　for　the　roof　structure,　five-level　stretching　scheme　with　*-shaped　tension　sequence　can　well　control　the　maximal　displacement　and　internal　force　of　structure　during　stretching,　which　is　the　optimal　construction　and　stretching　scheme.　Under　the　consideration　of　various　unfavorable　load　combinations,　the　maximum　stress　of　each　component　is　lower　than　the　strength　design　value　of　the　component　during　the　construction　of　the　roof　structure,　which　meets　the　requirements　of　the　code　and　the　structure　is　safe.　©　2022　Science　Press.　All　rights　reserved.