Benthic　diatoms　are　the　primary　beach　vegetation　on　sandy　coasts,　acting　as　the　main　primary　producers　in　such　environments.　Changes　in　their　community　structure　and　biomass　can　have　substantial　impact　on　both　the　entire　micro-food　web　and　the　nearshore　shallow　marine　ecosystem.　This　study　focused　on　four　typical　beaches　along　the　southern　coast　of　China　(Fuzhou　Changle　Beach,　Xiamen　Huizhan　Beach,　Xiamen　Guanyinshan　Beach,　and　Beihai　Silver　Beach).　Analysis　of　benthic　diatoms　and　environmental　factors　revealed　that　the　distribution　of　benthic　diatom　communities　on　the　studied　beaches　is　influenced　by　elevation,　salinity　changes　due　to　freshwater　inputs,　sediment　composition,　and　hydrodynamic　factors.　The　most　important　factor　is　elevation,　which　reflects　the　location　of　the　beach　in　the　tidal　zone.　On　Beihai　Silver　Beach　and　the　Xiamen　beaches,　the　mid-tidal　and　low　tidal　zones　are　more　conducive　to　growth　and　reproduction　of　benthic　diatoms,　and　some　diatom　species　show　preference　for　different　tidal　zones.　On　dissipative　beaches,　benthic　diatom　abundance　peaks　in　the　mid-tidal　zone,　whereas　on　low　tidal　terrace　beaches,　diatom　abundance　is　generally　low　in　the　high　tidal　zone　and　relatively　high　in　the　low　tidal　zone.　Additionally,　low　tidal　terrace　beaches　exhibit　a　＇steep　increase　zone＇　of　diatom　abundance　at　the　junction　of　the　steep　and　gentle　slopes,　indicating　that　benthic　diatom　abundance　responds　more　to　this　type　of　beach　landform　than　to　that　of　dissipative　beaches.　©　2024　Elsevier　Ltd