Under the guidance of "correspondence between man and nature" chronomedicine life rhythm theory in Inner Canon of Yellow Emperor(《黄帝内经》), researching the onset rhythm of ischemic stroke has important realistic significance to guide the prevention of ischemic stroke currently. Concretely, on the aspect of year-rhythm, it should be paid attention that physiological manifestations of human body are different in different seasons. Different seasonal climate could influent disease onset differently. Different regimen should be used in different seasons. On the aspect of month-rhythm, the influence of the moon profit-loss changes on Qi-blood of human body should be concerned. On the aspect of day-rhythm, the influence of diurnal fluctuation and morning-dusk changes on Yin-Yang Qi-blood of human body should be concerned.