1.Ultrasound examination: It is convenient and easy to perform, and is very useful for preliminary determination of pancreatic tumors. It can also detect liver, intrahepatic and extrahepatic bile duct tumors, and is the most common method to diagnose pancreatic tumors. In addition, biopsy of the pancreas can be taken under ultrasound guidance to clarify the pathological diagnosis. However, the diagnostic accuracy of ultrasound examination is limited by the operator’s technique, the patient’s hypertrophy and the gas in the gastrointestinal tract. 2.CT scan examination: It is one of the most commonly used methods to diagnose pancreatic tumor. To diagnose pancreatic tumor, intensive CT must be done, otherwise it is impossible to judge the invasion of surrounding blood vessels and lymph node metastasis. The accuracy of fine needle aspiration (FNA) cytology examination under CT or ultrasound guidance for pancreatic cancer diagnosis is up to 85%, and its specificity is almost 100%. FNA may be particularly useful when there is no indication for surgery or when surgery is not desired, whether for pancreatic tail or body damage or metastatic lesions. In addition, MRI diffusion imaging can determine the activity of the tumor. Retrograde cholangiopancreatography (ERCP) is particularly useful for diagnosing bile duct damage and obtaining biopsies of duodenal and jugular cancers. The image of the pancreas is rarely normal in the presence of pancreatic malignancy, and unresectable pancreatic cancer usually has bile duct dilatation. ERCP provides a basis for the possibility of duodenal papillotomy and localizes the endoprosthesis so that surgical decompression can be avoided. The insertion of endoscopy with the help of ultrasound provides a new method for diagnosing pancreatic tumors, and this technique offers the possibility of early diagnosis. 5.Glycan chain antigen 19-9 (CA19-9): It is an antigenic substance associated with adenocarcinoma. Normal reference value: serum <37 U/ml; clinical significance: ① In pancreatic cancer, gallbladder cancer and bile duct cancer, serum CA19-9 level is significantly increased, especially in patients with advanced pancreatic cancer, serum CA19-9 concentration can reach 400,000 U/ml, with a positive rate of about 7 singular 9%. CA19-9 levels are also elevated in acute pancreatitis, cholecystitis, cholestatic cholangitis, cirrhosis, hepatitis, etc. CA19-9 tests should be combined with imaging tests. The final diagnosis of pancreatic cancer still requires pathological or cytological evidence, so pancreatic aspiration under ultrasound guidance or CT guidance is very important.