Marine　shell　resources　have　received　great　attention　from　researchers　owing　to　their　unique　merits　such　as　high　hardness,　good　toughness,　corrosion　resistance,　high　adsorption,　and　bioactivity.　Restricted　by　the　level　of　comprehensive　utilization　technology,　the　utilization　rate　of　shells　is　extremely　low,　resulting　in　serious　waste　and　pollution.　The　research　shows　that　the　unique　brick-mud　structure　of　shells　makes　them　have　diverse　and　good　functional　characteristics,　which　guides　them　to　have　great　utilization　potential　in　different　fields.　Hence,　this　review　highlights　the　constitutive　relationship　between　microstructure-function-application　of　shells　(e.g.,　gastropods,　cephalopods,　and　amniotes),　and　the　comprehensive　applications　and　development　ideas　in　the　fields　of　biomedicine,　adsorption　enrichment,　pHotocatalysis,　marine　carbon　sink,　and　environmental　deicer.　It　is　worth　mentioning　that　marine　shells　are　currently　well　developed　in　three　areas:　bone　repair,　health　care　and　medicinal　value,　and　drug　carrier,　which　together　promote　the　progress　of　biomedical　field.　In　addition,　an　in-depth　summary　of　the　application　of　marine　shells　in　the　adsorption　and　purification　of　various　impurities　such　as　crude　oil,　heavy　metal　ions　and　dyes　at　low-cost　and　high　efficiency　is　presented.　Finally,　by　integrating　thoughts　and　approaches　from　different　applications,　we　are　committed　to　providing　new　pathways　for　the　excavation　and　future　high-value　of　shell　resources,　clarifying　the　existing　development　stages　and　bottlenecks,　promoting　the　development　of　related　technology　industries,　and　achieving　the　synergistic　win-win　situation　of　economic　and　environmental　benefits.　©　2023　Elsevier　B.V.