Using the genomic DNA of Streptomyces hygroscopicus as a template,transglutaminase gene segments were obtained by PCR amplification.The recombinant plasmid pGEX-TGase was transformed into E.coli to get the recombinant strain BL21/pGEX-TGase.The recombinant strain produced fusion protein induced by lactose and the conditions of induction were optimized.Expression products existed mainly in the form of inclusion bodies.Dilution and urea gradient liquid chromatography was used to refold the inclusion bodies successfully.The target proteins with electrophoretical purity and activity of 29 U/mg were purified by GST affinity column.