The determination of full-length 16S rDNA sequence and nifA gene segments of root nodule bacterium strain HJ06 isolated from Acacia crassicarpa showed that strain HJ06 had above 95% similarity with the genus Rhizobium. The nifA gene segments of HJ06 have 99.3% isogenesis with nifA genes of Klebsiella pneumoniae and 97.8% isogenesis with genes ofNifF, NifL, NifA and NifB proteins of K. oxytoca.