Age patients with cognitive impairment are often accompanied by circadian rhythm disturbance. Studies have shown that clock genes are involved in cognitive processes, and their abnormal expression is closely related to the occurrence and development of a variety of age related cognitive disorders. Based on the brief introduction of clock gene, this review summarizes the research advances of clock gene in several age related cognitive disorders, so as to provide a new target for early prevention, diagnosis and treatment of cognitive disorders in elder patients.