[Objective] The study was to express and characterize the fusion protein of goose β-defensin (AvBD) 12 in Escherichia coli. [Methods] The cDNA of goose AvBD12 was cloned into EcoR I and Xho I sites of pProEX-HTa vector. The recombinant expression plasmid was translated into E. coli Rosseta and the bacteria were induced by isopropyl β-D-1-thiogalactopyranoside (IPTG). The recombinant protein was purified. Furthermore, antibacterial activity and salt ionic stability of the recombinant protein were determined by colony-counting assays. [Results] It was demonstrated by Tricine-SDS-PAGE that the recombinant protein (molecular weight, 12 kD) was produced as insoluble bodies in the cells. The recombinant protein showed extensive antibacterial activity against bacteria, including E. coli, Micrococcus tetragenus, Salmonella pullorum, Bacillus subtilis, and Staphylococcus aureus. At high NaCl concentrations, the antibacterial activity of goose AvBD12 decreased significantly. In addition, goose AvBD12 showed little hemolytic activity. [Conclusion] Recombinant goose AvBD12 exhibited extensive antibacterial activity. High salt concentration significantly decreased its antibacterial activity. In addition, AvBD12 showed little hemolytic activity.