Objective To investigate the hazard of hypertension at initial diagnosis ages.Methods Using stratified cluster sampling,6 091 adults aged more than 18 years with/without hypertension were interviewed;meanwhile their blood pressures were measured.The hazard of hypertension at initial diagnosed age was analyzed with survival analysis.Results The prevalent rate of hypertension was 19.9%and the average initial diagnosed age of hypertension was 52.0?13.12)yrs.The hazard persistently increased with the age after 35 years old for male,and reached its peak of prevalent rate(26%)at the age of 75 years for female.Not significant difference of hazard existed between male and female.Conclusion Our data indicated that there is a close relationship between the risk of hypertension onset and the age,the hazard increasing with ages,especially for the population aged over 35 years old.Therefore,an early prevention of hypertension should be taken from adolescent period.