Objective: To investigate the relationship between the intra-abdominal hypertension (IAH) and degree of severity of acute pancreatitis (AP). Methods: Eighty AP patients admitted from February 2014 to February 2015 were selected. Of the patients, 49 cases were mild AP (MAP group) and 31 cases were severe AP (SAP group) according to their APACHE II scores at admission. The intra-abdominal pressure (IAP) of the patients was monitored via indirect bladder pressure measurement, 4 h per session for 5 d, and those with IAP value higher than 12 mmHg in two consecutive measurements were diagnosed as IAH. The incidence of IAH between the two groups was compared, and the correlation between IAP value and APACHE II score was analyzed; the incidence of adverse clinical events between cases with and without occurrence of IAH among SAP patients was compared, and the predictive values of APACHE II score and IAP for adverse clinical events were assessed by ROC curve analysis. Results: The incidence of IAH in SAP group was significantly higher than that in MAP group (45.2% vs. 0%, P<0.05), and the results of Pearson correlation analysis showed that there was a positive correlation between IAP value and APACHE II (r=0.752, P<0.05); the incidence of each adverse clinical event in cases with IAH was significantly higher than that in cases without IAH among SAP patients (P<0.05), and the AUC of IAP value for predicting adverse clinical events was significantly greater than that of APACHE II score (0.892 vs. 0.610, P<0.05). Conclusion: IAH is closely related to the degree of severity of AP, and it also may affect the clinical outcome of AP patients. IAP has important clinical value in predicting the risk of adverse clinical events in SAP patients.