Abstract: One pathogenic strain originally isolated from Sinvnovacula constricta was named 12#. 16S rDNA of strain 12# was amplified by PCR and the full-length of 16S rDNA sequence was determined. Using the NCBI BLAST database, this sequence was compared. The 16S rDNA sequence analysis indicated that strain 12# shared above 95% homology with some Aeromonas punctata. In the hylogenetic framework of bacterial classification, the strain 12# belongs to Aeromonas punctata. In phylogenetic tree, it was concluded that stain 12# and Aeromonas punctata sequences constituted a branch and this strain shared above 99% 16S rDNA sequence homology with Aeromonas punctata. So, we assure that strain 12# is Aeromonas punctata. Keywords: Sinvnovacula constricta，Aeromonas punctata，16S rDNA，Phylogenetic analysis，Identification.