Abstract: Objective: To express gastric cancer related gene GCRG224 using thioredoxin fusion expression system and prepare human GCRG224 fusion protein.Methods: GCRG224 cDNA with complete open reading frame was amplified by PCR from plasmid pGEM-T,and then was cloned into thioredoxin fusion expression vector pET102/D-TOPO.The recombinant plasmid was further transformed into E.coli BL21 strain.After induction with IPTG,the thioredoxin/GCRG224 fusion protein was expressed in E.coli.The product was obtained by means of direct purification from a denaturing polyacrylamide gel.Results: SDS-PAGE analysis showed the thioredoxin/GCRG224 fusion protein with relative molecule mass of 16.8ku was over expressed.The thin layer gel scanning analysis showed that the yield of GCRG224 fusion protein was 22.3% of the total bacterial protein.The product was obtained with a purity of about 100% by means of direct purification from a denaturing polyacrylamide gel.Conclusion: The thioredoxin/GCRG224 fusion protein is successfully expressed in E.coli and the product with high purity is obtained,which lie the foundation for the further function research and antibody preparation.