Autoimmune pancreatitis, or AIP for short, has been recognized since 1961 as a chronic inflammation and sclerosis of the pancreas due to autoimmune factors, but it was not officially named until 1995, and AIP was classified as a subtype of chronic pancreatitis in 2001. The incidence of AIP is about 1.8%-6%, but recently it has been reported that its incidence is far from low. AIP is often misdiagnosed as a pancreatic tumor and pancreatic resection surgery is often performed because the imaging manifestations of AIP are: diffuse or limited enlargement of the pancreas, often accompanied by stenosis of the pancreatic duct and bile duct; in serology: abnormal elevation of serum IgG4. IgG4 is abnormally elevated. If there is a puncture biopsy of the pancreatic tumor, basically to confirm the diagnosis. AIP is sensitive to hormone therapy, so if AIP is highly suspected clinically, hormone therapy can be tried, and if the mass remits after treatment, the diagnosis of AIP should be considered. In conclusion, AIP is a special type of chronic pancreatitis, which is very easy to be misdiagnosed clinically, so we should raise awareness of the disease. Patients without a history of alcoholism, with imaging suggestive of inflammatory masses in the pancreas and elevated IgG4, should consider the possibility of AIP and try hormone therapy first, which can avoid the pain of surgery in such patients. The positive attitude should be taken.