Soda　lakes　are　one　of　the　most　stable　naturally　occurring　alkaline　and　saline　environments,　which　harbor　abundant　microorganisms　with　diverse　functions.　In　this　study,　culture-independent　molecular　methods　were　used　to　explore　the　genetic　diversity　of　glycoside　hydrolase　(GH)　family　10　and　GH11　xylanases　in　Lake　Dabusu,　a　soda　lake　with　a　pH　value　of　10.2　and　salinity　of　10.1%.　A　total　of　671　xylanase　gene　fragments　were　obtained,　representing　78　distinct　GH10　and　28　GH11　gene　fragments　respectively,　with　most　of　them　having　low　homology　with　known　sequences.　Phylogenetic　analysis　revealed　that　the　GH10　xylanase　sequences　mainly　belonged　to　Bacteroidetes,　Proteobacteria,　Actinobacteria,　Firmicutes　and　Verrucomicrobia,　while　the　GH11　sequences　mainly　consisted　of　Actinobacteria,　Firmicutes　and　Fungi.　A　full-length　GH10　xylanase　gene　(xynAS10-66)　was　directly　cloned　and　expressed　in　Escherichia　coli,　and　the　recombinant　enzymes　showed　high　activity　at　alkaline　pH.　These　results　suggest　that　xylanase　gene　diversity　within　Lake　Dabusu　is　high　and　that　most　of　the　identified　genes　might　be　novel,　indicating　great　potential　for　applications　in　industry　and　agriculture.