Objective To investigate the therapeutic effect of adeno-associated virus (AAV)-mediated gene transduction of high mobility group box-1 protein (HMGB1) antibody on sepsis. Methods Sixty female C57 mice were evenly randomized into 2 sets, and each set was divided into 3 groups (n=10):AAV-HMGB1 antibody group, AAV-control-IgG group, and normal saline group, and the mice were injected intramuscularly with 60 μL of AAV-HMGB1 antibody virus, 60 μL of AAV-control-IgG virus, and 60 μL of normal saline in the left rectus femoris muscle in the 3 groups, respectively. All mice were subjected to cecal ligation and perforation 4 weeks later to establish sepsis models. The 14-d survival rate of mice in the first set was observed. Serum levels of inflammatory factors (interleukin[IL]-6, IL-1β and tumor necrosis factor α[TNF-α]) were measured in the blood obtained from the angular vein of mice in the second set, and pathological sections were taken from the heart, liver, lung, kidney and small intestine tissues. Results The HMGB1 antibody produced by the AAV-HMGB1 antibody gene transduction had a protective effect against sepsis in mice, 90% (9/10) of septic mice survived until day 14 post-modeling in the AAV-HMGB1 antibody group, while only 60% (6/10) and 50% (5/10) of mice survived on day 14 postmodeling in the normal saline group and the AAV-control-IgG group, respectively. The serum levels of inflammatory factors (IL-6, IL-1β and TNF-α) were significantly lower in the AAV-HMGB1 antibody group compared with those in the normal saline and AAV-control-IgG groups (all P<0.05). The AAV-HMGB1 antibody produced by the AAV-HMGB1 antibody gene transduction had a significant protective effect on the lung tissue, but not on other organs. Conclusion AAV-mediated gene transduction of HMGB1 antibody can neutralize HMGB1 in the serum by high expression of HMGB1 antibody, thus reducing the level of inflammatory factors in septic mice, improving pathological changes in vital organs and possibly reducing mortality in septic mice, which is expected to be a new strategy for the treatment of sepsis.