A　hierarchical　nanosized　pure　Si-Beta　zeolite　was　firstly　prepared　via　a　micro-zone　synchronous　crystallization　method　by　steam-assisted　conversion　taking　inorganic　silicon　sources　as　raw　material.　Neither　zeolite　seeds　nor　fluoride　mineralizing　agent　was　required,　only　a　bit　of　organic　template　agent　(TEAOH/SiO2　=　0.05)　was　sufficient　for　constructing　a　self-sustaining　plate-like　nanosized　aggregation　with　high　surface　area　(631.09　m2/g)　and　pore　volume　(0.7　cm3/g)　after　24　h　period,　much　less　than　reported　(TEAOH/SiO2≥0.54,　7–21　d).　The　pure　Si-Beta　zeolite　also　had　a　superior　hydrophobicity　than　that　of　hydrothermal　synthesis　due　to　the　advantage　of　micro-zone　mass　transfer.　All　the　properties　of　resulting　samples　were　investigated　by　comprehensive　characterizations,　including　X-ray　diffraction,　scanning　and　transmission　electron　microscopy,　nitrogen　adsorption-desorption,　water　adsorption,　Flourier　transform　infrared　and　solid　state　29Si　nuclear　magnetic　resonance.　Importantly,　a　“micro-zone　synchronous　crystallization”　mechanism　was　proposed　to　explain　the　formation　of　mesoporous　structure　and　intrinsic　micropores,　so　as　to　providing　the　theoretical　guidance　for　one-step　synthesis　of　hierarchical　Beta　and　other　zeolites.　©　2019　Elsevier　Inc.