Autoimmune pancreatitis (AIP) is a special type of chronic pancreatitis mediated by autoimmunity. The classic manifestation of AIP is diffuse pancreatic enlargement, some of which are characterized by focal enlargement. Clinically, it is divided into diffuse AIP (DAIP) and focal AIP (FAIP) according to morphology. FAIP can be clinically manifested as obstructive jaundice, peripancreatic lymphadenopathy and vascular involvement, which may mimic pancreatic cancer (PC). CT/MRI is the important imaging tool for diagnosing pancreatic diseases. However, due to the overlap of the imaging features of FAIP and PC, it is challenging to differentiate the two by CT/MRI. Endoscopic ultrasound (EUS) can clearly display the pancreatic parenchyma and pancreatic duct system and has become a routine modality for the evaluation of pancreatic diseases. The aim of this study is to construct a diagnosis model for distinguishing between FAIP and PC by comparing the EUS characteristics of the two, and further validate its diagnostic efficacy.