Abstract: Objective To evaluate the relationship between obesity index and hypertension risk and to identify the cut-off point for the prevention of hypertension. Methods Stratified cluster random sampling method was used to select a total of 5 809 adults aged 20-69 years from three settings of the Third China's National Physical Fitness Surveillance of Liaoning province including Shenyang,Dandong and Chaoyang city.Physical examination was conducted for the subjects without antihypertensive medications. Results Among the 5 809 subjects,the prevalence of high normal blood pressure and hypertension was 16.92% and 24.89%,respectively.The prevalences of high normal blood pressure and hypertension in men(20.98%,31.57%)were significantly higher than those in women(12.94%,18.33%)(P<0.01).Multivariate logistic regression results showed that older than 40 years and body mass index(BMI)were risk factors,and female gender was a protective factor for high normal blood pressure.For hypertension,older than 30 years,BMI and waist circumference were risk factors,and female gender was a protective factor.After adjusted for age and gender,risks of high normal blood pressure and hypertension increased by 1.38(95% confidence intervalCI:1.28-1.50)and 1.57 (95% CI:1.39-1.78)times with the increase of per standard deviation of BMI.The risk of hypertension increased by 1.37(95% CI:1.20-1.56)times with the increase of per standard deviation of waist circumference.Based on the maximal Youden's index,the cut-off points of BMI to identify high normal blood pressure were 24.0 kg/m² for men and 24.3 kg/m² for women,and the cut-off points to identify hypertension were 25.1 kg/m² for men and 24.3 kg/m² for women.The cut-off points of waist circumference to identify hypertension were 87.0 cm for men and 80.6 cm for women.On the basis of sensitivity higher than 80%,the cut-off points of BMI to identify high normal blood pressure were 23.0 kg/m² for men and 22.3 kg/m² for women,and the cut-off points of BMI to identify hypertension were 23.4 kg/m² for men and 22.8 kg/m² for women.The cut-off points of waist circumference to identify hypertension were 82.0 cm for men and 76.9 cm for women. Conclusion Risk of hypertension increases with the increments of BMI and waist circumference,and BMI is more strongly associated with hypertension than waist circumference.