A bovine interferon-kappa (BoIFN-κ) gene was amplified， which encodes a protein of 215 amino acids sharing 63% identity with human IFN-κ. BoIFN-κ was demonstrated to have antiviral and antiproliferative activities. Moreover， BoIFN-κ was shown to be highly sensitive to trypsin， however， it remained stable despite changes in pH and temperature. Result showed that BoIFN-κ can bind with bovine type I IFN receptors， and the antiviral activity can be blocked by antibodies against type I IFN receptors or BoIFN-κ. Additionally， BoIFN-κ can induce the transcription of Mx1， ISG15 and ISG56 gene， as well as the expression of Mx1 protein. The NF-κB， ISRE， and BoIFN-β promoter can all be activated by BoIFN-κ. This study revealed that BoIFN-κ exhibits the typical characteristics of type I IFNs and exerts antiviral activity via activation of the JAK-STAT signaling pathway. Overall， these findings will enrich the current knowledge about IFN-κ and facilitate further research on the role of type I IFN in antiviral defense responses in bovine.