At present, the clinical diagnosis of Alzheimer's disease (AD) is mainly based on clinical history, however, the sensitivity and accuracy is limited. Positron emission computed tomography can accurately diagnose AD early by glucose metabolism imaging and biomarker imaging. Magnetic resonance imaging provides the basis for early diagnosis and identification of AD by structural imaging and functional imaging. In recent years, the multi-modality imaging technology closely combines radiology and nuclear medicine, which can more accurately diagnose AD.