It　is　difficult　to　tunnel　in　the　coastal　region　of　complex　formations　due　to　the　lack　of　research　into　the　adaptability　of　shield　tunneling.　A　new　method　based　on　the　fuzzy　comprehensive　evaluation　model　and　analytic　hierarchy　process　(AHP)　approach　was　proposed　to　evaluate　the　adaptability　of　shield　tunneling.　Furthermore,　an　improved　genetic　algorithm　(IGA)　was　introduced　to　calculate　the　weight　of　the　index,　which　overcomes　the　defect　of　the　AHP　in　terms　of　consistency　testing.　The　evaluation　model　of　adaptability　was　established　based　on　the　comprehensive　analysis　of　the　factors　influencing　adaptability　in　coastal　complex　formations.　A　case　study　on　the　adaptability　evaluation　of　the　Peng-Cai　shield　zone　of　Xiamen　Metro　was　introduced　to　verify　the　application　of　the　proposed　method.　The　results　indicated　that　the　evaluation　result　accords　with　engineering　practice　and　the　proposed　method　can　be　used　to　evaluate　the　adaptability　of　shield　tunneling.