Alzheimer’s disease （AD） is a progressive neurological degenerative disease with an insidious onset and has the clinical features of memory loss， personality and behavioral disorders， cognitive impairment， and mental disorders， as well as the typical pathological changes of neuroinflammatory plaques and neuronal fibrillary tangles. At present， the structural imaging techniques commonly used in clinical practice， such as computed tomography and magnetic resonance imaging， can only find AD patients with structural changes of brain tissue and cannot realize the early and super-early diagnosis of the disease. Functional imaging and molecular imaging can assess the progression and changes of AD respectively from the functional and molecular levels. Functional imaging techniques include CT perfusion imaging， functional magnetic resonance imaging， and arterial spin labeling and have an indicative role in the diagnosis of preclinical AD by detecting the changes in local cerebral blood perfusion to evaluate the change of brain activity and function. Molecular imaging techniques include positron emission tomography， single-photon emission computed tomography， and magnetic resonance spectrum imaging， and based on the identification of AD biomarkers， corresponding radioactive tracers are developed to identify and combine the characteristic pathological molecules of AD， so as to realize the early identification of AD from the pathological changes of cells. Compared with structural and functional imaging techniques， molecular imaging techniques have a greater role in the early identification， grading assessment， and treatment outcome prediction of AD and provide new technical paths for the clarification of pathogenesis and the development of new drug targets. This article summarizes the latest research advances in various imaging techniques for AD， analyzes the clinical and scientific research value of related techniques， evaluates the advantages and disadvantages of different techniques， and discusses future prospects and challenges.