Objective:Contrasting serum nitric oxide, superoxide dismutase catalase and between the acute biliary pancreatitis group and the normal group,to discuss the significance of each index. Methods:Forty clinical acute biliary pancreatitis patients were selected randomly and divide into two types(mild ABP and severe ABP), 50 policlinic medical examination people were selected as the comparison, serum NO,SOD and CAT levels were examined in every object respectively. Results:Serum NO and CAT levels in ABP patients were higher than those in normal people(P < 0.01) and elevated remarkably in SABP(P < 0.01). While serum SOD in ABP patients was lower than that in normal people(P < 0.01) and descended remarkably in SABP(P < 0.05). Conclusion:NO and CAT participated in ABP development, whose levels were parallel to ABP status. SOD descended according to ABP status,providing that extrinsic SOD might alleviate the severity of ABP.