Alzheimer disease（ AD） is one of the most common degenerative disorders of the nervous system. It is mainly manifested as progressive cognitive decline， affecting the ability of daily living and abnormal mental behavior. Recent studies have found that in early AD， hippocampal neurofunction is hyperactive. Hippocampal hyperfunction is a compensatory mechanism to maintain memory function， but through the study of animal models， it is found that the cognitive function of animal models with normal hippocampal nerve activity is better preserved. The animal model of hippocampal hyperactivity is associated with cognitive dysfunction， and the inhibition of hippocampal hyperactivity by drugs can improve cognitive function. The discovery of this phenomenon has led to a major shift in our understanding of the disease process of AD， and has had important implications for the direction of research in the treatment of AD.