Abstract: To analyze the genetic differentiation of Tibet mini-pigs and its relationships with other pig breeds including European and domestic pigs, the sequences of nucleotides and amino acids of Cyt b were sequenced. The results showed that there were 9 mutation sites in Cyt b gene of Tibet mini-pigs and the nucleotide diversity was 0.078 9. Compared with pig breeds from Europe, there were 16 mutations in domestic pigs in China. There was significant difference between T-C switch at site 420 and G-A switch at site 883. The amino acid sequence analysis indicated that Tibet mini-pigs, compared with pig breeds from Europe, were different at three amino acid sites, especially at site 295, the partial Tibet mini-pigs together with other pig breeds were Valine, while another pig populations were Isoleucine at this site. The results indicated that the partial Tibet mini-pigs had very closely blood relationships with Bama Miniature pigs, Guizhou Xiang pigs and WZS pigs, and there was genetic differentiation in Tibet mini-pig group.