The pancreas is a retroperitoneal organ and most pancreatic cancers originate from the pancreatic ductal epithelium. The density of early pancreatic cancer is not much different from normal pancreatic tissue, therefore, early diagnosis of pancreatic cancer is extremely difficult. Therefore, it is extremely difficult to diagnose pancreatic cancer at an early stage. Those who are diagnosed clinically are usually in the middle and late stages. Due to the rich blood supply of pancreatic tissue, pancreatic cancer in the middle and late stages is prone to spread and metastasis and has a poor clinical prognosis, therefore, pancreatic cancer is the “king of cancers”. CT, MRI (MRCP) and PET-CT are important for the diagnosis of pancreatic cancer, how to choose them for clinical application? Generally speaking, CT scan+enhancement has advantages in detecting and staging pancreatic masses and should be preferred; MRI has advantages in determining tumor invasion of blood vessels and biliopancreatic ducts; whole body PET-CT has advantages in determining and staging lymph nodes and distant metastases of tumors, but it is expensive. Therefore, when deciding which test to choose, we should consider the patient’s initial diagnosis, follow-up diagnosis, efficacy and prognosis assessment, as well as the patient’s general nutritional status, history of contrast allergy and economic status, etc. The three imaging tests can only complement each other’s information and cannot replace each other.