A　sustainable　defect-engineering　strategy　for　the　dealumination　of　Y　zeolite　is　described.　This　strategy　includes　the　green　synthesis　of　a　well-crystallized　Y　zeolite　with　point　defects　arising　from　the　incorporation　of　Fe　atoms　by　using　Fe-containing　perlite　and　the　subsequent　preparation　of　ultra-stable　Y　(USY)　zeolite　by　efficient　steaming　dealumination.　The　systematic　characterizations　verify　that　Fe　atoms　originally　existing　in　the　perlite　are　incorporated　into　the　as-synthesized　Y　zeolite　and　function　as　point　defects,　leading　to　the　distortion　of　framework　Al.　The　step-by-step　investigation　of　dealumination　process　shows　that　vacancies　are　formed　by　the　extraction　of　framework　Fe　in　ammonium　exchange,　and　the　framework　dealumination　is　promoted　under　the　combined　effect　of　the　distorted　framework　Al　and　the　formed　vacancies　during　steaming　treatment.　The　resulting　USY　zeolite　owns　excellent　features　in　(hydro)thermal　stability,　pore　structure　and　acid　property,　and　exhibits　outstanding　catalytic　performance　in　the　cracking　of　n-octane　and　1,3,5-triisopropylbenzene.