Objective To investigate the CT and MRI features of the autoimmune pancreatitis (ALP).Methods CT and MRI data of fourteen patients with AIP who were confirmed by histology and/or steroid therapy were retrospectively analyzed.Ten patients underwent CT examination, and seven patients underwent MRI, while three patients underwent both CT and MRI examinations.Results It was showed that diffuse (n =11 ) or local ( n = 3 ) enlargement of pancreas.CT features showed that the hypoattenuation pancreatic lesions on unenhanced CT (n = 10);segmental pancreatic duct could be seen in five patients;stenosis of common bile duct in the head of pancreas was observed in 5 patients;the capsule-like structure around lesions was seen in seven patients.Delayed homogeneous enhancement was showed on enhanced CT.MRI features included homogeneous ( n = 3) and heterogeneous ( n = 4) hyperintense on T1 WI with fat-suppression images and homogeneous ( n = 3 )and heterogeneous (n =4) hyperintense on T2WI with fat-suppression images.Pancreatic duct could be seen in four patients.MRCP showed pancreatic duct stenosis in the head of pancreas ( n = 1 ) and segmental pancreatic duct (n = 2).Stenosis of common bile duct in the head of pancreas was showed in 5 cases.The capsule-like structure around lesions was showed in seven patients.No pancreatic calcification was revealed, and no significant pancreatic duct dilation was detected ( ＞3 mm) in all 14 patients.Conclusions The CT and MRI manifestations of AIP had characteristic features such as sausage-like changes of the pancreas, capsule-like structure around the lesions, diffuse or local pancreatic duct stricture, and stenosis of common bile duct in the bead of pancreas.