Objective To observe the effects of rosiglitazone, an agonist of peroxisome proliferator-activated receptor ɣ (PPARɣ), on pulmonary injury in septic rats induced by cecal ligation puncture. Methods Eighty healthy male Wistar rats were randomly divided into 5 groups: sham group(group SHAM); cecal ligation puncture group(group CLP); rosiglitazone group(group ROSI): rats were intravenous injected with rosiglitazone 0.3mg/Kg 30 minutes before CLP; GW9662 group(group GW): rats were intravenous injected with GW9662 0.3mg/Kg 30 minutes before CLP; GW9662 plus rosiglitazone group(group GW+ROSI): rats were injected intravenously with GW9662 0.3mg/Kg 30 minutes before CLP and then with rosiglitazone 0.3mg/Kg 15 minutes before CLP. Eight rats were sacrificed at 6 and 24 h after CLP respectively in each group. Blood was reserved for the measurement of the level of plasma TNF-α by ELISA and lung tissues were removed for the detections of lung wet/dry ratio, lung myeloperoxidase(MPO) activity, and lung tissue HMGB1mRNA expression by real-time PCR. Results Compared with group SHAM, the lung W/D ratio, MPO activity, plasma TNF-α level and the lung tissue HMGB1mRNA expression were significantly increased in group CLP, group ROSI, group GW and group GW+ROSI(P<0.05). Compared with group CLP, group GW and group GW+ROSI respectively, the lung W/D ratio, MPO activity, plasma TNF-α level and the lung tissue HMGB1mRNA expression were significantly decreased in group ROSI(P<0.05). Conclusion Rosiglitazone can decrease the plasma TNF-α level and the lung tissue HMGB1mRNA expressionα level and attenuate the pulmonary edema and inflammation in septic rats by CLP. It can have protective function on pulmonary injury.