Abstract: Complete sequence of mature interferon-τ gene from Chinese Hostein was cloned and sequenced for the first time(GenBank Accession Number: DQ680846、DQ680847). Its CDS sequence is 519bp, encoded 172 amino acid residues of bovine mature interferon-τ protein. All bovine interferon-τ sequences is divided into four groups by cluster analysis. A novel group(τ4) and six novel variant forms(τ1e、τ3f、τ3g、τ3h、τ4a、τ4b)were found. DQ680846 is a variant forms in τ4, signed τ4a; DQ680847 is a variant forms in τ3, signed τ3f. The nucleotide sequence homology of all bovine interferon-τ genes are 92.7%~99.8%, and the amino acid sequence homology of all bovine interferon-τ protein are 88.5%~99.4%. The nucleotide sequence homology between interferon-τ4a and other bovine interferon-τ is 94.0%~97.1%. The nucleotide sequence homology between interferon-τ3f and other bovine interferon-τ is 92.9%~99.6%. The amino acid sequence homology between interferon-τ4a and other bovine interferon-τ, interferon-τ3f and other bovine interferon-τ is 91.4%~96.0% and 88.5%~99.4% respectively. The results suggest bovine interferon-τ gene is high-degree conservation in the evolution. The secondary structure of bovine interferon-τ mature protein was predicted by MLRC and the results show that five α-helices(A-E) is substructure of interferon-τ mature protein, and Asn78、Cys1 、Cys29、Cys99、Cys139、Ile143、Lys160 and the 11 amino acid residues from carboxyl terminus are high-degree conservation region, which are essential for structure and function of bovine interferon-τ.