As　the　most　important　component　of　marine　siliceous　organisms,　diatoms　are　vital　primary　producers　of　the　ocean　that　are　often　used　as　indicators　of　paleoenvironmental　change.　To　understand　the　response　of　sedimental　diatoms　to　regional　environmental　changes　and　the　factors　affecting　the　distribution　of　sedimental　diatoms　in　the　Taiwan　Strait,　this　study　quantified　and　classified　the　diatoms　found　in　surface　sediments　collected　during　four　surveys　from　2019　to　2020.　Overall,　118　diatom　taxa　and　44　genera　were　identified　with　total　diatom　abundance　of　8-27　353　valves/g.　Four　diatom　assemblages　representing　different　environments　were　identified.　Among　them,　assemblage　I　represented　a　coastal　environment,　assemblage　II　comprised　warm　water　species　of　a　coastal　environment,　Assemblage　III　represented　a　coastal　environment　affected　markedly　by　exorheism,　Assemblage　IV　represented　a　group　with　lowest　diatom　abundance.　Seasonal　variation　in　total　diatom　abundance　was　controlled　by　seven　environmental　factors:　depth,　sea　surface　salinity,　mean　grain　size,　silicate,　nitrite,　nitrate,　and　phosphate.　Spatiotemporal　variation　in　each　of　the　diatom　assemblages　was　substantial　and　strongly　affected　by　various　currents,　upwelling,　and　low-salinity　water.　Specifically,　it　was　found　that　the　succession　of　diatom　assemblages　reflects　change　in　the　range　of　influence　of　local　warm　currents.