Objective To explore the ideal choice of feeding artery which is used for regional arterial infusion (RAI) in severe acute pancreatitis. Methods Forty-five patients with SAP were treated with RAI. The ideal feeding artery was that can supply entire pancreas according to arteriography and can maximize concentration of drug at pancreatic tissue. The pancreatic arteriography was considered as the final objective evidence for choice. Results (1)Gastroduodenal artery was chosen as feeding artery in forty-four cases, and superior mesenterlc artery was chosen in only one case because of vascular abnormity. (2)According to splenic arteriography, blood of splenic artery was supplied to spleen chiefly, and only partial tail of pancreas was applied by splenic artery. (3)According to celiac trunk arteriography, blood of celiac trunk could be supplied to entire pancreas, but a considerable proportion of the total blood was supplied to spleen through splenic artery and liver through hepatic artery proper.Therefore, the drug utilization index was lower. (4)According to gastroduodenal arteriography, blood of gastroduodenal artery could be supplied to entire pancrea, and almost all of the blood that contains drug flowed into pancreas. Therefore, the drug utilization index was higher. Conclusions Gastroduodenal artery is the ideal choice of artery which is used for regional intra-arterial infusion in sever acute pancreatitis. Pancreatic arteriography should be applied routinely when yever acute pancreatitis was treated with RAI.