Abstract: Based on the general situation and geology condition of the Xiamen Xiang'an sub-sea tunnel engineering, the paper has analyzed the risks in constructing the tunnel were analyzed. A detailed construction solution has been drawn for the tunneling of the sub-sea deep weathered rock troughs. The construction measures mainly include: to enhance prediction and investigation of geology; to adopt advanced technology of full face curtain grouting and supplementary grouting to tunneling; to use pre-supporting method by pre-grouting tubes in small diameter; to excavat by the method of double-side pilot heading, to install facilities outside the boreholes to prevent water emerging, and to pour concrete wall and prevent water by grouting. The solution has provideed technical basis for the safety construction of this kind of tunnel.