Antimicrobial peptides are promising candidates for therapeutic and industrial application owing to their broad spectrum. In this work, a cost-effective method for expression of a potent antimicrobial peptide, bovine lactoferricin derivative LfcinB15-W4,10, has been developed. The oligonucleotide encoding the peptide was linked to generate different oligomeric oligonucleotide segments containing from one to nine but eight tandem copies which was inserted individually to the E. coli expression vector pET32a. The thioredoxin fusion peptides were successfully expressed and detected with different molecular weight on SDS gel, respectively. Among the monomer and other multimeric peptides, the tetramer was expressed at the highest level. After purification, more than 10 mg of tetramer with 99% purity was obtained from 1 l culture and exhibited similar antimicrobial activity as synthetic LfcinB15-W4,10 monomer. The expression system in this study provides a potential production method for lactoferricin derivatives and other antimicrobial peptides in research and industrial applications.