Abstract: 【Objective】 To construct and identify Saccharomyces cerevisiae expression strain Y187 containing outer membrane protein gene omp25 in B.abortus. 【Method】 The gene omp25 was amplified and obtained from B. abortus vaccine strain S19 by PCR with a pair of specific primers and ligated into pGM-T vector，pGM-T-omp25 is then obtained and identified by PCR、restriction analysis and sequencing. pGM-T-omp25 and vector pGBKT7 were digested by EcoRⅠ/SalⅠ, purify and ligate gene omp25 and pGBKT7. Constructed pGBKT7-omp25 was transformed into Y187 and identified by PCR、transcription activation and toxicity testing. 【Result】 Outer membrane protein gene omp25 was cloned successfully. Through PCR、restriction analysis and sequencing, it was confirmed that bait vector pGBKT7-omp25 was successful constructed and transformed into Y187. Obtained transformant yeast Y187 is inactive and nontoxic，too. 【Conclusion】 Saccharomyces cerevisiae expression strain Y187 containing outer membrane protein gene omp25 in B.abortus was constructed successfully and can facilitate study on the molecular mechanism between infection and female livestocks abortion . Key words: B. abortus；gene omp25；Saccharomyces cerevisiaeY187；eukaryotic expression