Abstract: Objective:To construct thioredoxin and APE/ref-1 fusion protein expression vector and to investigate their subcellular localization of the fusion proteins in 293Tcells. Methods: The APE/ref-1 cDNA was cloned by RT-PCR from PC12 cell and APE/ref-1-EGFP fusion protein expression vector was constructed through subclone.Thioredoxin cDNA was subcloned into pDSred1-1 from pQE30-TRX plasmid by PCR,and thioredoxin-DsRed fusion protein expression vector was constructed in pCMV5 plasmid. The expression and subcellular localization of the fusion protein in 293T cells transfected with the vectors by calcium phosphate was analyzeed by fluorescent microscopy. Results: The results demonstrated that thioredoxin--DsRed and APE/ref-1-EGFP fusion proteins expression vectors was successfully constructed and expressed in 293T cells. APE/ref-1-EGFP fusion protein was located only in the nucleus,and thioredoxin- DsRed fusion protein was located from cytoplasm to nucleus. Conclusion: This study has paved the way for further study on the dynamic interaction between thioredoxin and APE/ref-1 fusion proteins.