Cognitive dysfunction is a prevalent neuropsychiatric disorder, commonly observed in patients with degenerative diseases of the central nervous system, severe trauma and post-surgery, with complex mechanisms involved. Epigenetics is a genetic variation in the regulation of gene expression that differs from genetics in that it can be involved in the regulation of many physiological functions by affecting numerous gene expression profiles. Increasing evidence suggests that epigenetic regulation plays an important role in the formation and maintenance of normal cognitive function. Key mechanisms of epigenetic regulation, including histone modification, DNA methylation, and non-coding RNA regulation, are associated with the development of cognitive dysfunction. Correcting these epigenetic regulatory disturbances has a mitigating effect on cognitive dysfunction. There is a close relationship between different epigenetic regulatory mechanisms, and their interaction regulates cognitive function. This review focuses on Alzheimer's disease (AD), a common central nervous system disorder, and summarizes and analyzes the role of epigenetic regulatory mechanisms in AD-related cognitive dysfunction, which can help to elucidate the epigenetic regulatory pathogenesis of AD-related cognitive dysfunction and provide new ideas for its prevention and treatment.