Abstract: Primers designed according to the mitochondrial gene sequences of Bos taurus reported was used to amplify and sequence jiulong yak’s D-loop region, and the whole sequence was obtained. Using Ovis aries as outgroup taxa, the phylogeny about the representative species of Bovinae (Poephagus grunniens, Poephagus mutus, Bos taurus, Bos indicus, Bison bison, Bison bonasus, Bubalus bubalis）was analyzed. The results showed that the length of D-loop was 893 bp, owning 87.4% homology with the Bos taurus D-loop sequence, there existed 17 bp deficiency. Among Bovinae, the percentage nucleotide sequence divergence between Poephagus grunniens, Poephagus mutus and American bison of Bison bison was 6.2%-6.8%，which was less than that of Bos taurus and Bos indicus in Bos (10.0%-11.3%). Phylogeny analysis found that Poephagus grunniens, Poephagus mutus and Bison bison were clustered first of all, indicating there was higher genetic comparability among them than that of Bos. Combining with the proof of paleontology, morphology, molecular biology, the data supports the point that Poephagus grunniens and Poephagus mutus are classified as an alone genus in Bovinae, that is Poephagus.