Abstract: The polymorphism of the serum transferrin was investigated in the blood samples from 74 Oura Tibetan sheep by means of PAGE. The results were as follows: five alleles including TF^A，TF^B，TF^C，TF^D and TF^M were showed in total on the locus of serum transferrin in the examined Oura Tibetan sheep, and of them the TF^B，TF^C and TF^D were the preponderant alleles, and their frequencies were 0.4122，0.2973 and 0.2162. Nine genotypes including TFAB，TFAC，TFAD，TFBB，TFBC，TFBD，TFBM，TFCC and TFDD were showed, of them TFBC，TFBB，TFBD，TFCC and TFDD were the preponderant genotypes, and their frequencies were 0.2703，0.1622，0.1622，0.1351 and 0.1216. The gene heterozygosity on the locus of serum transferrin was 0.6921.

Key words: Oura Tibetan sheep; serum transferrin; polymorphism