Abstract: 【Abstract】 Objective To investigate the protective effection of tanshinone on endothelial cells of severe acute panreatitis (SAP) rats and the effection of tanshinone on apoptosis of aorta endothelium. Methods Using 8% L-arginine intraperitoneal to inject in rats, 4.4 mg/g per time, repeat injection 1 hour later, for establishing SAP model. Model rats were randomly divided into SAP group and tanshinone group. 20 mg/kg Sodium Tanshinon Ⅱ Asilate i.p. was applied to tanshinone group,while the saline was used to replace Sodium Tanshinon Ⅱ Asilate in SAP group. Twelve rats of each group were sacrificed at 12 h, 24 h after treatment. The pathological changes in pancreatic tissues were observed.Abdominal aorta samples were collected for terminal deoxynucleotidyl transferase mediated dUTP biotin nick end labelling (TUNEL) and reverse transcription PCR (RT-PCR) tests. The blood samples were collected from abdominal aorta for analysis. Detections: ① The concentration of Von Willebrand factor (vWF), soluble endothelial protein C receptor (sEPCR), tumor necrosis factor alpha (TNF-α) and the serum levels of nitric oxide (NO) were quantitative messured by ELISA. ②The apoptosis of aorta endothelium cell was examined using TUNEL method. ③ Bcl-2 and Bax mRNA expression were measured by RT-PCR. Results The pathological changes of pancreatic tissues were more severe in SAP group than those in tanshinone group. Compared with SAP group, treatment with tanshinone effectively inhibited TNF-α (P<0.05), vWF (P<0.05)and sEPCR (PBcl-2 mRNA (P<0.05), Bcl-2 mRNA/Bax mRNA ratio (P<0.05) and the expression of BaxmRNA (P<0.05) were decreased significantly. Conclusion Sodium Tanshinon ⅡAsilate can lighten the SAP rats aortic endothelial injury and apoptosis of endothelial cells can reduce endothelial damage of SAP rats by TNF-α expression suppression.