The reseach was carried out in the ICU of Bach Mai Hospital, and was aimed to investigate the effect of intra-abdominal pressure in prognostic and monitoring of acute pancreatitist. The authors have done a prospective, observational study on 133 patients with acute pancreatitist, admitted ICU Bach Mai Hospital from 6/2008 - 6/2011. The results showed that: + There was 68,4 percent of patients with acute pancreatitist had intra abdomial hypertention. + The intra abdominal pressure was the prognotic and monitoring factors in acute pancreatitist. Conclusions: this is the first study to validate the intraabdominal pressure in patients with acute pancreatitist, research group need more studies so it can be applied in clinical practice.