In　this　work,　core-satellite　assemblies　and　exonuclease　assisted　double　amplification　strategy　is　developed　to　produce　surface-enhanced　Raman　scattering　(SERS)　biosensor　towards　ultrasensitive　detection　of　biotoxin.　In　the　presence　of　target　molecules,　the　exonuclease　III　(Exo　III)　assisted　efficient　recycling　amplification　provides　an　excellent　pathway　for　the　fabrication　of　core-satellite　SERS　sensor.　Briefly,　the　proposed　strategy　includes　the　following　double　amplifications:　(i)　Exo　III　induced　target-related　signal　amplification;　(ii)　core-satellite　assemblies　assisted　formation　of　SERS　“hot-spots”　induced　signal　amplification.　To　show　the　applicability　of　the　suggested　strategy,　the　detection　of　ochratoxin　A　(OTA),　one　of　the　most　toxic　and　widely　distributed　biotoxin,　is　demonstrated　as　an　example.　The　results　show　that　the　limit　of　detection　(LOD)　of　OTA　is　0.83　fg　mL−1　(S/N　=　3).　On　the　basis　of　the　DNA　aptamer　induced　specific　target　recognition,　hence　our　sensing　strategy　is　easy　to　be　expended　to　the　ultrasensitive　detection　of　other　targets,　e.g.,　DNAs,　RNAs,　and　other　molecules　that　have　corresponding　DNA　aptamers.　©　2020　Elsevier　B.V.