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　excavate　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　provided　technical　basis　for　the　safety　construction　of　this　kind　of　tunnel.