Abstract: Objective To investigate the changes of hepatic IL-9-secreting lymphocytes in MHV-3-induced fulminant hepatitis in mice for the analysis of involvement of IL-9 in the mechanisms of immune- mediated liver injury. Method MHV-3-induced fulminant hepatitis model was established in mice,and the percentage of hepatic IL-9-secreting T lymphocytes was determined by flow cytometry. Results The percentage of hepatic IL-9-producing CD4⁺T cells increased from 1.87±1.36% to 4.77±0.42% at 48h after viral inoculation（P<0.05）,while the percentage of hepatic CD4^-CD8^-（DN） T cells who also expressed IL-9 at 72h after infection was 7.83±3.30%,which was significantly higher than that at 24h（P<0.05）. Conclusion The increased expression of IL-9 from hepatic CD4⁺T and DNT lymphocytes may contribute to immune-mediated liver injury in MHV-3- induced fulminat hepatitis in mice.