Objective To creat a pancreatitis-associated acute lung injury(PALI) model in rats by retrograde infusion of 5% sodium tauroculam(TAC) into the biliopancreatic duct.Methods\ A modified procedure of retrograde infusion of TAC into the biliopancreatic duct was used to induce acute hemorrhagic necrotizing pancreatitis(AHNP) in rats.Rats were divided into AHNP,control (laparotomy only,no TAC injection) and dexamethasone(DXM) treatment(after successfully TAC injection,supramaximal dose of DXM was injected) group.The rats were killed at 3,6,12 hours after operation.Serum amylase and lipase were assayed.The middle lobe of right lungs were removed and used for lung edema histopathological evaluation.The ratio of protein content in bronchialo-alveolar lavage fluids (BALFs) to serum proteins was used as lung permeability index.Results\ In the AHNP group,lung permeability index,wet to dry weight ratio and histopathological alterations were increasing with time,higher at 6,12 hours than at 3 hours determined by one way ANOVA analysis(P<0.05).No significant difference was found in the 6,12 hours groups in regard to the former two injury indexes.Compared with AHNP group,injury was less severe in DXM treatment group at 6,12 hours after operation. Conclusions\ Apparent lung injury occurs at 6 hours after pancreatitis induced by retrograde infusion of TAC into the biliopancreatic duct in rats.The pulmonary morphological and functional changes in the model rats are similar to those in AHNP patients with acute lung injury,suggesting its value in PALI studies.