The MRI data of 13 patients with autoimmune pancreatitis (AIP) were retrospectively analyzed. The results showed that the pancreas diffusely enlarged in 10 of 13 cases, and focally enlarged in 3cases. There were 13 cases with decreased signals on T1WI and mildly hyperintense on T2WI in the area with pancreatic lesions, 11 cases with thickened capsule-like structure showing moderate-low signal T1WI and low signal T2WI,and delayed enhancement in dynamic contrast-enhanced MRI, and 10 cases with stenotic common bile duct at the level of pancreas with proximal cholangiectasis. The findings in 9 cases were remarkably improved in followup MRI after glucocorticord treatment.