Objective To study the effects of endothelin (ET) on acute pancreatitis in rats. Methods The acute edematous pancreatitis (AEP) and hemorrhagic necrotizing pancreatitis (AHNP) model of rats were induced by cerulein and dextran-110 and endothelin-1 was administered on AEP rats via intravenous injection. Serum amylase, plasma ET and 6-Keto-PGF1α, pancreas hostologic observation were determined. Results The serum concentration of amylase increased markedly in AHNP rats, and there was a significant difference between AHNP and AEP (Ｐ＜0.01). A dose of extrinsic ET-1 may induce the conversion of AEP to AHNP in rats. The degree of pancreatic damage correlates positively with the level of the plasma ET. Conclusion Endothelin might take part in the development of acute pancreatitis, and play a key role in the conversion of AEP to AHNP.