Abstract: Objective: To investigate the circadian rhythm of the hypertensive cerebral hemorrhage attacks for better prevention of the disease.Methods: One hundred twenty nine patients hypertensive cerebral hemorrhage were classified on the attack time at 6-hour interval from 0:00 o'clock during the 24 hours of the day,and the occurrence of the attacks were analyzed based on the time segments. Results: The peak time of occurrence of the acute cerebral hemorrhage attacks was from 6 am to 12 o'clock at noon.Conclusions: The occurrence of cerebral hemorrhage attacks is obviously a circadian tendency,high risk period is on the morning.