Abstract: To provide a new vaccine for oral immunization of transmissible gastroenteritis virus (TGEV), attenuated Salmonella typhimurium harbouring S/N double fusion genes of (TGEV) was constructed and identified. The S gene fragment (2.1 kb) and the N gene fragment (1.2 kb) were respectively amplified from the recombinant plasmid 19TS and 19TN of TGEV by RTPCR, and then the two gene fragments were successively inserted into the eukaryotic expression vector pVAX1 to construction the recombinant eukaryotic expression plasmid pVAXS/N that expressing the SN double fusion gene. The plasmid pVAXS/N was identified by PCR and restrictive digestion, and then the pVAXS/N was transfected into COS7 cells through liposome transfection to identify the expressions of the two target genes by indirect immunofluorscence assay. The plasmid pVAXS/N was transformed by electroporation into attenuate S. typhimurium SL7207, the stability of pVAXS/N in SL7207 (pVAXS/N) cultured in vitro was detected. The transcription of pVAXS/N in mouse ileal tissue cells orally immunized with SL7207 (pVAXS/N), BALB/c mice were inoculated orally with SL7207 (pVAXS/N) at different dosages to detect the safety and stability in vivo. The results showed that the recombinant plasmid pVAXS/N was constructed correctly and the expression of S gene and N gene were detected in COS7 cells. The transcription and expression of S/N double fusion gene were detected in mouse ileal tissue cells after 3 days infected with SL7207 (pVAXS/N). The recombinant bacteria SL7207 (pVAXS/N) was highly stable cultured with Kanamycin Resistance medium in vitro. The recombinant SL7207 (pVAXS/N) were all safe to mouse at dosage of 0.5×109, 1×109 and 2×109 CFU. The SL7207 (pVAXS/N) were eventually eliminated from the spleen and liver at about four weeks postimmunization. These results indicated that the recombinant bacteria SL7207 (pVAXS/N) had good safety and stability, which lay a foundation for oral immunization of TGEV.