The　applications　of　fluorescence　resonance　energy　transfer(FRET)are　coming　to　be　one　of　the　simplest　and　most　accessible　strategy　with　super-resolved　optical　measurements.Meanwhile,nanomaterials　have　become　ideal　for　constructing　FRET-based　system,due　to　their　unique　advantages　of　tunable　emission,broad　absorption,and　long　fluorescence(FL)lifetime.The　limitations　of　traditional　FRET-based　detec-tions,such　as　the　intrinsic　FL,auto-FL,as　well　as　the　short　FL　lifetime,could　be　overcome　with　nanoma-terials.Consequently,numbers　of　FRET-based　nanomaterials　have　been　constructed　for　precise,sensitive　and　selective　detections　in　biological　systems.They　could　act　as　both　energy　donors　and/or　acceptors　in　the　optical　energy　transfer　process　for　biological　detections.Some　other　nanomaterials　would　not　partic-ipate　in　the　energy　transfer　process,but　act　as　the　excellent　matrix　for　modifications.The　review　will　be　roughly　classified　into　nanomaterial-involved　and　uninvolved　ones.Different　detection　targets,such　as　nucleic　acids,pathogenic　microorganisms,proteins,heavy　metal　ions,and　other　applications　will　be　reviewed.Finally,the　other　biological　applications,including　environmental　evaluation　and　mechanism　studies　would　also　be　summarized.