Abstract: This paper systematically expounds the research advance and theoretical connotation of the kidney generating the marrow and unblocking brain collaterals, and points out the relationship between the kidney, marrow and brain in terms of structure and function. The article proposes that brain marrow insufficiency is the key to the onset of cognitive impairment. Kidney deficiency runs through cognitive impairment, and phlegm and blood stasis are important pathological factors. The treatment should mainly focus on tonifying the kidney. Through the kidney-tonifying method, the purposes of nourishing the brain and marrow, strengthening the brain and memory, and helping to eliminate phlegm and remove blood stasis are proposed. Representative prescriptions for tonifying kidney yang and kidney yin are proposed to provide ideas and methods for the clinical prevention and treatment of cognitive impairment and the expansion of its prescription and medication selection.