To study the efficacy and mechanism of Salvia miltiorrhizae injection in the treatment of severe acute pancreatitis. SAP rat models were prepared and randomly divided into model control group and treated group. The sham-operated group was also set. At 3, 6 and 12 h after operation, the mortality rate, ascitic volumes, pathological changes in the pancreas, contents of amylase and endotoxin in plasma as well as IL-6, IL-18, ET-1 and NO in serum, the staining intensity of Bax and NF-kappaB p56 proteins, and the changes in apoptosis index of pancreatic cells in rats in each group were observed. The pathological severity scores (at 3, 6 and 12 h after operation), contents of plasma endotoxin (at 6 and 12 h after operation) and serum IL-6 (at 6 and 12 h after operation) were significantly lower than those in model control group (P < 0.05, P < 0.01 and P < 0.01, respectively); the staining intensity and the product of the staining intensity and positive staining rate of Bax protein in the pancreas were significantly higher than those in model control group (P < 0.01). Salvia miltiorrhizae is able to reduce the contents of plasma endotoxin and serum IL-6, promote the expression of Bax protein in pancreas, improve the pathological changes in the pancreas, and decrease the mortality rate of rats, thereby showing therapeutic effect on rats with SAP.