In　order　to　evaluate　the　structure　safety　of　cut-and-cover　section　of　Xiamen　sub-sea　tunnel　caused　by　lack　of　ground　load-bearing　capacity,　the　cut-and-cover　tunnel　is　modeled　as　a　structure　loaded　by　earth　and　water　pressures.　The　deflections,　inner　forces　and　safet　of　the　cut-and-cover　tunnel　structure　are　analyzed　by　a　structure　analytical　software　named　as　ANSYS,　and　the　structure　safety　factors　are　calculated.　In　conclusions,　the　cut-and-cover　tunnel　structure　is　safe　before　backfilling,　but　the　structure　safety　is　not　enough　because　of　the　loads　of　backfilling　self-weight.　It　is　suggested　that　the　ground　of　the　cut-and　cover　tunnel　should　be　treated　by　reinforced　measures.