Abstract: The complete 18S rRNA gene of Babesia orientalis parasited in buffalo in China was obtain by PCR. It was sequenced and then blasted. The result indicated that the parasite belonged to the genus Babesia .The 1 700 bp complete gene sequence was compared with 15 other Babesia sp. availabled in GenBank. The data were analyzed and a phylogenetic tree was established. The result indicated that the parasite was close to Babesia sp. of South Africa and B.ovis, and the distant was far to B.bigemina and B.bovis. This result indicated that it was no doubtful that it was a new species. It proved that the Buffalo babiesiosis was not mixinfected by B.bigemina and B.bovis .