Objective To investigate the effect of administration intravenously of rosiglitazone (ROSI) on severe acute pancreatitis (SAP) in rats and its mechanisms. Method Fifty-four male Wistar rats were randomly divided into sham operation group (SO group), severe acute panereatitis model group (SAP group) and rosiglita-zone pretreatment group (ROSI group),18 rats in each group.SAP model was induced by retrograde inufsion of 5% sodium taurecholate into the biliopancreatic duct. The rats in SO group and SAP group were injected with 10% DMSO (0.2 ml/100 g) by femoral vein 30 minutes piror to the operation. In ROSI group,rosiglitazone partes ae-quales(6 mg/kg) was injected instead of 10% DMSO. Rats were killed at 3, 6 and 12 h after operation. Serum amylase level and myelopemxidase activity were detected. Pancreatic tissue samples were stained with hematoxylin and eosin for histopathological evaluation. Reverse transcription-polymerase chain reaction was used for detecting the levels ofTNF-α mRNA and ICAM-1 mRNA in pancreatic tissue. Results Amylase level, myeloperexidase ac-tivity, pathologic score and the expression of TNF-α and ICAM-1 mRNA were increased significantly in SAP group at each time point than those in SO group (P<0.05). Compared with SAP group, pretreatment with rosiglitazone reduced serum amylase level and pathologic score at time point of 6 h and 12 h (P<0.05), decreased myeloper-oxidase activity at 12 h (P<0.05), downregulatied the expression of TNF-α mRNA at all time pointy, (P<0.05),ICAM-1 mRNA at 6 h and 12h(P<0.05). Conclusions Rosightazone has the effect on pancreatitis in SAP through downregulating the expression of TNF-α mRNA and ICAM-1 mRNA.