Abstract: Phylogenetic diversity of the strains in the genus Halomonas from hypersaline environments in Lop Nur region was investigated using traditional culture－dependent method and 16S rRNA phylogenetic analysis. Total nine strains isolates exhibited the closest phylogenetic affinity and highest sequence similarity (98. 4%－100%) to Halomonas ventosae, Halomonas elongata, Halomonas caseinilytica, Halomonas caseinilytica, Halomonas taeanensis, Halomonas pantelleriensis, Halomonas sulfidaeris, Halomonas salina and Halomonas cupida, respectively.. In addition, a novel bacterium, GT 123, was isolated from a salt lake Luobupo. The affiliation of strain GT 123 with the genus Halomonas was confirmed by 16S rRNA gene sequence comparisons. The most closely related species was Halomonas anticariensis, which showed a 16S rRNA gene sequence similarity of 95%. On the basis of the data from this polyphasic study, strain GT 123 represented a novel species of the genus Halomonas. The results indicated that there was not only abundant phylogenetic diversity of the genus Halomonas, but also some unknown bacterial groups existed in hypersaline environments in Lop Nur region.