Sulfide　in　oil　refinery　wastewater　was　selectively　oxidized　to　sulfur　in　a　biological　desulfurization　reactor.　When　sulfide　concentration　in　the　influent　was　605.3　mg·L-1,　90.7%　sulfide　removal　was　achieved　and　80.8%　of　sulfide　was　converted　into　sulfur.　DNA　was　extracted　from　the　reactor　to　construct　a　16S　rDNA　gene　library　for　the　analysis　of　biological　communities.　Fifty-one　clones　were　randomly　selected　and　their　partial　16S　rDNA(1　400　bp)　was　sequenced.　Sequencing　results　were　analyzed　using　the　BLAST　algorithm　at　NCBI　and　a　phylogenetic　tree　was　constructed,　identifying　10　bacterial　groups.　The　dominant　bacterial　community　in　the　reactor　is　γ-Proteobacteria,　which　account　for　76.6%　of　the　sequences.　The　majority　of　γ-Proteobacteria　belong　to　desulfurizing　bacteria,　such　as　Halothiobacillus　sp.　(66.7%),　Thiovirga　sp.　(25.6%)　and　Pseudomonas　sp.　(7.7%).　The　phylogenetic　analysis　demonstrates　that　the　desulfurization　system　has　evolved　into　a　unique　microbial　community　structure　consisting　mainly　of　chemoautotrophic　desulfurizing　bacteria,　rather　than　heterotrophic　bacteria.　©　2016,　Science　Press.　All　right　reserved.