Objective: To investigate the characteristics of paralytic ileus (PI) during the course of severe acute pancreatitis (SAP) and its influence on the prognosis. Methods: The clinical data of 45 patients with SAP admitted from February 2011 to March 2012 were reviewed. Of the patients, 19 cases were complicated with PI (SAP+PI group) and 26 cases without PI (SAP group). The clinical characteristics of SAP with associated PI and its prognosis were analyzed. Results: CT scan showed the incidence of the accumulation of gas and fluid in small intestine and colon, hugely distended bowel loop and bowel wall edema in SAP+PI group was 100%, 73.7% and 78.9% respectively, while in SAP group, the first two signs were not obvious and the incidence of bowel wall edema was 50% (P=0.048). Compared with SAP group, the gastric retention volume, incidence of feeding intolerance (FI) and jaundice, and the intra-abdominal pressure (IAP) as well as the extent of IAP change were significantly elevated in SAP+PI group (all P<0.05). In addition, the length and cost of hospitalization, and mortality rate were increased in SAP+PI group compared with SAP group (all P<0.05). Univariate analysis indicated that FI, IAP (>15 mmHg), jaundice and gastric retention volume (>250 mL/d) were important factors affecting the prognosis of SAP patients (all P<0.05). Conclusion: The predominant signs of SAP with PI in CT images are the accumulation of gas and fluid and hugely distended bowel loop. SAP patients with associated PI are frequently complicated by intra-abdominal hypertension, jaundice, FI and gastric retention, which may contribute to the increased mortality of these patients.