Potential target proteins binding to VirB4 of type Ⅳ secretion system were screened during Brucella infected bovine embryonic trophoblast cells .Brucella VirB4 genes were amplified by PCR with species-specific primers .Expression vector pGBKT7-virB4 was constructed and analysed by sequencing and restriction enzymes ,transforming to the yeast strain Y187 and testing self-activation and toxicity .The cells model and cDNA library of bovine embryonic trophoblast cells infected with Brucella abortus strain were constructed respectively .Utilizing yeast two-hybrid system was employed to screen the target proteins of bovine embryo trophoblastic cells which was conjunctive with virB4 .These proteins were detected by real-time fluo-rescence quantitative PCR .The results suggested that bait plasmid pGBKT7-virB4 was successfully transformed into the Y187 and there was no toxicity and self-activation;the cDNA library of bovine embryonic trophoblast cells infected with Brucella abortus strain was constructed .There screened 13 positive plasmids in which Q10 and SLC3A2 were up-regulated at the mRNA level .In this paper ,we reported the interactions between the VirB4 protein of Brucella and the bovine embryo trophoblastic cells ,which provide an upstream work for further elucidating the pathogenesis of Brucella infection of the host cell .