This　paper　investigates　the　correlation　across　China’s　marine　industries　and　the　relationship　between　marine　and　land　industries　in　coastal　provinces　using　the　Gray　Correlation　Theory.　Our　results　show　an　increasing　similarity　of　marine　industry　structures,　a　low　allocation　efficiency　of　marine　resources　as　well　as　growing　but　homogeneous　competition　between　regions.　To　avoid　the　problem　of　“isomorphism”　in　marine　industry,　we　should　focus　on　policy　measures　such　as　optimizing　the　overall　spatial　distribution　of　marine　economy,　promoting　the　development　of　the　new　marine　industry,　strengthening　the　correlation　between　marine　and　land　industries,　building　a　complementary　development　pattern　for　marine　economy,　expanding　new　areas　for　industrial　development　and　fostering　new　economic　growth　points.　©　2018　Taru　Publications.