The　extinction　property　of　a　two　species　competitive　stage-structured　phytoplankton　system　with　harvesting　is　studied　in　this　paper.　Several　sets　of　sufficient　conditions　which　ensure　that　one　of　the　components　will　be　driven　to　extinction　are　established.　Our　results　supplement　and　complement　the　results　of　Li　and　Chen　[Extinction　in　periodic　competitive　stage-structured　Lotka-Volterra　model　with　the　effects　of　toxic　substances,　J.　Comput.　Appl.　Math.,　2009,　231(1),　143-153]　and　Liu,　Chen,　Luo　et　al.　[Extinction　and　permanence　in　nonautonomous　competitive　system　with　stage　structure,　J.　Math.　Anal.　Appl.,　2002,　274(2),　667-684].　©　2019　Huang　et　al.,　published　by　De　Gruyter.