Objective To investigate the effect of hydroxyethyl starch (HES 130/0. 4) on the expression of aquaporin 1 (AQP-1) and liver injury in rats with severe acute pancreatitis(SAP).Methods Forty-eight male SD rats were randomly divided into three groups: Sham, SAP, and HES;each group was divided into 6 hour and 24 hour timepoints, with 8 in each subgroup. An SAP model was induced by injecting 5% sodium taurodeoxycholate into the biliary pancreatic duct. AMY, ALT,AST and water content in the liver were measured and TNF-a was examined by ELISA, and the expression of liver AQP-1mRNA was determined by RT-PCR, and the expression of liver AQP-Ⅰ protein was evaluated by immunohistochemical methods. Results Compared with the Sham group, the level of AMY, ALT, AST, TNF-a, water content, AQP-1mRNA and AQP-1 protein increased significantly in the SAP group (P＜0.05). Compared with the SAP group, the level of AMY, ALT, AST,TNF-a, water content, AQP-1mRNA and AQP-1 protein decreased significantly in the HES group (P＜0.05). At 6 hours, the expressions of liver AQP-1mRNA were (0. 402 ± 0. 023), (0. 811 ±0. 032) and (0. 595 ± 0. 015) in the Sham, SAP, and HES groups, respectively; at 24 hours, they were(0. 412 ± 0. 017), ( 0. 823 ± 0. 029) and (0. 607 ± 0. 021 ), with significant differences between each group (P＜0. 05). At 6 hours, the expressions of liver AQP-1 proteins were (2.07±0.25),(6.90±0.38)and (4.48±0.29) in the Sham, SAP and HES groups, respectively;at 24 hours, they were (2. 32±0. 31 ), (7. 04 ± 0. 32) and (4. 56 ± 0. 35), with significant differences between each group (P＜0. 05). Compared with the SAP group, the pathology of the pancreas and liver ameliorated significantly in the HES group. Conclusions Hydroxyethyl starch 130/0.4 may ameliorate liver injury of severe acute pancreatitis and alleviate the capillary leak. AQP-1 may play a role in the capillary leak caused by the liver injury of severe acute pancreatitis.