Effective　removal　of　strontium　isotopes　in　radioactive　waste　streams　has　important　implications　for　the　environment　and　the　sustainable　development　of　nuclear　energy.　In　this　work,　a　zirconium　phosphate/18-crown-ether-6　(ZrP/18C6)　composite　was　prepared　using　the　intercalation　method　by　loading　crown　ether　into　zirconium　phosphate.　The　composite　was　structurally　and　morphologically　characterized　by　XRD,　FT-IR,　XPS,　and　SEM.　The　adsorption　experiments　of　Sr2+　onto　the　ZrP/18C6　composite　were　conducted　as　a　function　of　temperature,　pH,　Sr2+　concentration　and　competing　ions.　The　results　indicate　ZrP/18C6　can　adsorb　98.6%　of　Sr2+　within　30　minutes　at　an　Sr2+　concentration　of　100　mg　L−1　and　maintain　a　high　removal　rate　with　a　distribution　coefficient　of　7　×　105　mL　g−1　when　Sr2+　is　at　a　low　level　of　4.28　mg　L−1.　The　ZrP/18C6　composite　reached　a　maximum　adsorption　capacity　of　195.74　mg　g−1　at　an　Sr2+　concentration　of　380　mg　L−1,　which　is　significantly　higher　than　the　43.03　mg　g−1　of　α-ZrP.　The　adsorption　performance　of　Sr2+　onto　ZrP/18C6　is　not　significantly　affected　by　temperature,　pH　and　competing　ions.　Furthermore,　the　adsorption　kinetics　and　thermodynamics　were　analyzed　based　on　the　adsorption　data　obtained　in　the　present　work.　It　is　shown　that　the　adsorption　of　Sr2+　onto　ZrP/18C6　follows　the　pseudo-second-order　model　and　the　Langmuir　monolayer　model,　respectively.　Additionally,　the　adsorption　mechanism　of　Sr2+　by　ZrP/18C6　is　discussed.　©　2023　The　Royal　Society　of　Chemistry.