Abstract: A pair of specific primers was designed based on the reported Bm86 gene of Boophilus microplus，the Bm86 gene was cloned by PCR using the plasmid pMD18-T-Bm86 as templates，and subcloned into the prokaryotic plasmid pGEX-4T-1. The recombined plasmid was transformed into E. coli BL21（DE3） and followed by expression of the protein induced by different concentration of IPTG for different time. SDS-PAGE showed that the recombinant plasmid pGEX-4T-1/Bm86 expressed a fusion protein Bm86-GST （Mr 94 000） after being induced with IPTG. High level expression of Bm86-GST was found at 1 mmol/L IPTG condition after incubation for 8 h at 37 ℃， and the expression level of the recombinant Bm86-GST reached up to 29% of total E. coli proteins. Western blotting analysis showed that the recombinant Bm86-GST was recognized by the rabbit anti-B. microplus positive serum．

Key words: Boophilus microplus, Bm86 gene, Expression