Abstract: Objective To construct a eukaryotic expression plasmid of human DC-SIGN gene containing a FLAG tag and detect its expression in eukaryotic cell 293T. Methods Human DC-SIGN gene containing FALG tag was constructed by PCR and inserted into a eukaryotic expression vector pIRES-neo. The recombinant plasmid pIRES-neo-FLAG-DC-SIGN was transfected to the 293T cells, and its expression was detected by FACS, IMF and Western blot. Results The gene sequence of human DC-SIGN containing FLAG was consistent with that of design. PCR and enzyme digestion analysis showed that the recombinant plasmid pIRES-neo-FLAG-DC-SIGN was successfully constructed and its expression was detectable by FACS, IMF and Western blot. Conclusion The recombinant plasmid pIRES-neo-FLAG-DC-SIGN can be successfully constructed and expressed in 293T cells, which can provide a necessary basis for the research of DC targeting vaccines.