In order to investigate the expression of Notch-1 in rats with acute pancreatitis (AP) and its relation with apoptosis of pancreatic cells, mild AP (MAP) and severe AP (SAP) models were established by retrograde injection of different concentrations of sodium taurocholae into pancreatic duct. The apoptosis index and the expression of Notch-1 protein and mRNA were detected by using TUNEL, West blot and real-time PCR in MAP and SAP at different time intervals. The results showed that in MAP group the apoptosis index was significantly elevated during 4 to 24 h after induction of pancreatitis, but there was no significant difference among different time intervals. In SAP group, the apoptosis index reached the peak at 4th h after induction of pancreatitis, then gradually declined. There was significant difference in apoptosis index between MAP and SAP groups. Starting from 4th after induction of pancreatitis, the expression of Notch-1 in both MAP and SAP group was increased at different time intervals, but that in SAP group was significantly higher than in MAP group (P＜0.05). The expression of Notch in MAP and SAP groups reached the peak at 12th and 8th h respectively after induction of pancreatitis. It was concluded that there was significant difference in apoptosis index and the Notch-1 expression in different types of AP. The overexpression of Notch-1 could aggravate AP by inhibiting the apoptosis of pancreatic cells.