Abstract: In order to evaluate the structure safety of cut-and-cover section of Xiamen sub-sea tunnel caused by lack of ground load-beating capacity,the cut-and-cover tunnel is modeled as a structure loaded by earth and water pressures.The deflections,inner forces and safer 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.