Objective To investigate the relationship between gene expression of endothelin-3 (ET-3） and inflammation of acute pancreatitis （AP） in rats. Methods Fifty-four rats were divided randomly into 4 groups: sham operation group, AP group, arterial injection group and vein injection group. AP was induced by reverse intra-bile duct infusion 4.5% sodium taurocholate, treated with low dose dopamine 〔5 μg/（kg·min）〕 by injecting arterial or tail vein. Rats were sacrificed at 1， 6 and 24 h after the induction of AP. The mRNA expression of ET-3 was evaluated by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and pathological changes was observed in rats. Results Expression of ET-3 mRNA could be detected from 1 up to 24 h after the induction of pancreatitis. Expression of ET-3 mRNA of sham operation group was decreased significantly compared with other three groups. Expression of ET-3 mRNA showed a significant decrease by arterial injection dopamine than that by tail vein (P＜0.05， P＜0.01). The pathologic score in AP group was the highest, vein injection group was the next one, and score in sham operation group was the lowest. Conclusion There are significant relationship between inflammation of AP and expression of ET-3 mRNA. Dopamine administration by arterial injection is more effective than that by tail vein injection.