Objective To explore the secretion law of high mobility group box 1（HMGB1）in rat pancreatic acinar cells induced by trypsin activation peptide（TAP）and release of HMGB1 affected by ethyl pyruvate（EP）. Methods The experiment was performed in 12 SD rats. The pancreatic acinar cells of rats were taken out and then separated into three groups：control group， TAP group， and EP group. TAP was added into TAP group and EP group（keep TAP at a final concentration of 3 nmol/L）， respectively， but EP was added into EP group only （keep EP at a final concentration of 28 mmol/L）. The expressions of HMGB1 mRNA and protein were detected by using real-time quantitative reverse transcription polymerase chain reaction（RT-PCR）or Western blot at 3 h， 6 h， 12 h， and 24 h time point， respectively. The relationship between HMGB1 and TAP action time was explored by rank correlation. Results Compared with control group， the expressions of HMGB1 mRNA and protein were increased with prolongation of the TAP action in TAP group and EP group（P＜0.05）. Compared with TAP group， the expressions of HMGB1 mRNA and protein were decreased in EP group（P＜0.05）. The expressions of HMGB1 mRNA and protein were increased with prolongation of the TAP action（P＜0.05）， and were highest at 12 h time point（P＜0.01）in TAP group. There were positive correlation between the expressions of HMGB1 mRNA and protein and TAP action time（rs=0.971， P＜0.01；rs=0.966， P＜0.01）.Conclusions TAP can induce the release of HMGB1 in pancreatic acinar cells. There is positive relationship between TAP in early stage and HMGB1 in later period of acute pancreatitis. EP can inhibit the release of HMGB1.