Objective To evaluate the significance of Bedside Index for Severity of Acute Pancreatitis (BISAP) in the prediction of the severity and prognosis of acute pancreatitis (AP) in the elderly patients. Methods A total of 96 elderly patients with AP, admitted into Beijing Geriatric Hospital from Jan 2010 to Jun 2013 were recruited in this study. BISAP was used to predict the severity and prognosis of AP, and the results were compared with the results by Ranson’s criteria. Results Among the 96 patients, 63 patients were identified as mild AP, and 33 as moderate and severe AP. There was no significant difference in predicting the severity and prognosis of AP between BISAP and Ranson scores. BISAP had relatively high sensitivity in the prediction of moderate and severe AP. BISAP score had positive correlation with C reactive protein and blood glucose, and had negative correlation with serum calcium and albumin. Conclusion BISAP Score is a simple and practicable scoring system, and has significant value in predicting the severity and prognosis of AP in the elderly.