Abstract: The objective of the present study was to develop and apply an indirect immunohistochemistry method for detecting the antigenic distribution and expression regularity of pcDNA-DPV-gC in the experimentally vaccinated duckling tissues. Three-week-old Tianfu ducking were inoculated with different doses (50, 100 and 200 μg) of DPV gC DNA vaccine by intramuscular injection. At intervals of 4 h, 12 h, 1 day, 3 days, 5 days, 7 days, 2 weeks, 4 weeks, 6 weeks, and 10 weeks postvaccination (p.v.), two ducklings were randomly euthanatized and their organs (liver, spleen, lung, kidney, pancreas, brain, thymus, Harderian gland, bursa of Fabricius, duodenum, caecum, rectum and muscle of injected spot) were collected. Meanwhile, the indirect immunohistochemistry method was established to detect the antigenic distribution and expression regularity of pcDNA-DPV-gC in the experimentally vaccinated ducking tissues. The results showed that:①The positive staining were found in the liver, duodenum, caecum, rectum and muscle of injected spot at 1 day p.v., and the immunoreactivity in the muscle of injected spot was stronger than other organs. In addition, a drastic reduction of DPV gC antigen level were observed after the highest immunoreactivity at 2 weeks p.v., but still had a detectable vaccine antigen level in the liver, brain, duodenum, caecum and rectum at 10 weeks p.v.. Interestingly, there was scarcely detected positive signal in the pancreas throughout the immunologic process; ②The positive staining reaction for pcDNA-DPV-gC had a conspicuous discrepancy among the different tissues. The positive immunogenicity was mainly found in the liver, spleen, bursa of Fabricius, brain, duodenum, caecum, and rectum, which served as the principal sites for antigen localization. The DPV gC encoding glycoprotein could be expressed in the various types of cells, especially in the lamina propria mucosae cells of intestinal tract, the lymphocyte of splenic white pulp and red pulp and the nerve cement cells of pallium. ③According to the immunogenicity intensity and duration time, the positive staining in all tissues were in below order: duodenum, caecum, rectum > liver > bursa of Fabricius > spleen > brain > muscle of injected spot > thymus > lung > Harderian gland > kidney > pancreas. ④The signal intensity and duration time of different doses were in below order: 200 μg group > 100 μg group > 50 μg group. Different doses of pcDNA-DPV-gC could continuously express DPV gC encoding glycoprotein as early as 1 day p.v., and exist in those at least 10 weeks p.v. The results demonstrated that the immunization time of pcDNADPV-gC was a long period located in the experimentally vaccinated ducking tissues.