Abstract: Ribosomal small-subunit RNA gene-sequence of eight Chinese Babesia stocks infective to cattle, including one Babesia bigemina isolate, one B. bovis isolate, three Babesia ovata isolates, one Babesia major isolates and two unnamed Babesia sp. isolates (Babesia U sp.), were cloned and analyzed. The target DNA segments were amplified by PCR and the products were ligated into the pGEMT Easy vector for sequencing. The length of the 18S rRNA gene of all Babesia species involved in this study varied between 1 653～1 699 bp. The phylogenetic trees were constructed based on 18S rRNA sequence of the Chinese isolates as well as other species of Babesia available in GenBank. The results showed that Chinese isolates of Babesia bovis and Babesia bigemina were in the same branch with corresponding foreign isolates respectively; B. ovata transmitted by Haemaphysalis longicornis were locateded in the same group with B. ovata Korea, and homology among them exceed 96.5%; B. major transmitted by H. punctata was situated in another branch, and the homology with other bovine Babesia species is less than 92.5%; Two isolates B. U sp. is dispensed on the same branch with B. caballi, and the homology with other bovine Babesia species is less than 91.8%. These results indicated that there are five Babesia pecies infective for cattle in China, including B. bovis, B. bigemina, B. major, B. ovata and Babesia U sp.