Abstract: Diabetes mellitus is a chronic and metabolic disease affecting more than 400 million people in the world. The pathogenesis of type 1 and type 2 diabetes mellitus is associated with the decrease or functional impairment of pancreatic β cells. With long-term hyperglycemia, diabetic patients will develop cardiovascular disease, neuropathy, diabetic foot and other complications. This paper reviews the application research progress of different types of PET and SPECT molecular imaging in the function monitoring of pancreatic β cells, and early diagnosis of diabetic complications such as coronary artery disease, cardiomyopathy, autonomic neuropathy, brain abnormalities and diabetic foot in diabetic patients.