Objective: To review the clinical characteristics of pancreatic occupying lesions with initial presentation of acute pancreatitis (AP), for providing warnings of this condition. Methods: The data of 12 typical cases with above condition admitted between September 2010 and October 2014 were collected, and variables such as clinical findings, laboratory parameters and imaging features were comprehensively analyzed. Results: All of the 12 patients were admitted for AP; the male to female ratio was 11:1, which was remarkably higher than that (1.4:1) of pancreatic cancer. The urine amylase was markedly increased (>1 500 U/L) in all cases (100%), 8 cases (66.7%) were accompanied with evident radiating pain around the waist, 6 cases (50.0%) showed increased CA19-9 level, 6 cases (50.0%) had elevated serum bilirubin level and pancreatic duct dilation was found in 7 cases (58.3%). Five cases underwent radical surgery, and the other cases had non-surgical treatment or palliative operation due to loss of chance for radical surgery, and one of the cases (8.3%) undergoing palliative operation was pathologically proven to be chronic pancreatitis after operation. Conclusion: Among the AP patients, pancreatic occupying lesions should be taken into consideration in those with factors that include male sex, increased urine amylase, pancreatic duct dilation, and accompanied with pain radiating around the waist and persistent jaundice.