To investigate changes of serum nitric oxide (NO) levels and therapeutic effects of sodium nitroprusside (SNP) in acute hemorrhagic necrotizing pancreatitis (AHNP) in rats, one hundred and twenty Wistar rats were divided into three groups randomly (forty in each group) animal models of AHNP group were produced by retrograde injection of 5% sodium taurocholate into pancreatobiliary duct.In the treatment group SNP (0.05mg/100g) was injected intraperitoneally after AHNP models established and then repeated three hours later. In the control group only retrograde injection of normal saline (0.5ml) into pancreatobiliary duct was performed. The results showed: compared with the treatment group, serum NO and SOD levels were significantly lower in AHNP group (Ｐ＜0.05); serum amylase levels and pancreatic indexes were markedly higher in AHNP (Ｐ＜0.01 and Ｐ＜0.05 respectively);the mortality in 24 hours was significantly higher and survival time was significantly shorter in AHNP group (Ｐ＜0.01).Pathologic changes of pancreas were significantly severe in AHNP group. From the above results we can draw the conclusion that NO plays an important role in the pathogenesis of AHNP and SNP has therapeutic effects on AHNP in rats.