Abstract:Subsea tunnel is different from land tunnel and sea water level changes slightly relative to subsea tunnel depth. Automatic drainage is not adopted for subsea tunnel because its two exits are higher than underwater segment. Great hydrostatic pressure loads on the second lining structure. Lots of lining types about domestic and overseas subsea tunnels are investigated. According to subsea tunnel characteristics,subsea tunnel design theory and method are presented. Considering the geology and hydrology conditions of certain subsea tunnel,three lining structure types are adopted such as U-shape,ellipse and circle shapes. These three lining structures are computed with finite element method. Some valuable conclusions are made as follows:(1) lining of horse shape may sustain much water pressure in the condition of limited drainage;(2) it is reasonable that lining of ellipse sustains geological stress in great water pressure;(3) it is the most reasonable that lining of circle sustains geological stress while lining of full impermeability is adopted in subsea tunnel.