Abstract: Objective Research on the relation between blood pressure and body mass index,waist,waist-to-hip ratio in middle school students.Methods Parts of grade nine students in Ma'anshan city,Anhui province were selected to the somatometric measurement.Chi-square test and analysis of variance were used to analyze the relation between blood pressure and different measure index.Results The prevalence of overweight was 13.6% in male students and 6.9% in female students and there was a significant difference between male and female(χ²=54.772,P<0.001).The obesity rate in male and female was 5.0% and 2.6% respectively,there was also a significant difference between male and female(χ²=18.717,P<0.001).The blood pressure level and detection rate of high blood pressure among groups which divided by BMI,waist circumference and waist-to-hip ratio in boys and girls were of significant difference.The blood pressure was positively correlated with BMI,waist circumference and waist-to-hip ratio(P<0.01).Conclusion The risk for hypertension was increased in the middle school students in grade 9 with high body mass index,high waist circumference and high waist-to-hip ratio.Body mass index and waist circumference correlates more than waist-to-hip ratio with blood pressure,so it is important to control weight in suitable range to prevent hypertension.