Objective To analysis the time of acute cerebral stroke occurrence. Methods The occurrence time of 2675 patients with cerebral infarction (1925 cases,CI group) and intracerebral hemorrhage(750 cases,ICH group) were statisticed by 1 time unit per 2 h from 0∶00. Results There was a time-curve with double peaks of stroke occurrence,like as circadian rhythms of blood pressure in 24 h. ⑴ In CI group,the first peak was 6∶00~10∶00, the second peak was 18∶00~22∶00. The value of the first peak was higher than that of the second(P