Objective: To examine the relationship between obesity and carotid intima-media thickness (cIMT) in children and adolescents in order to provide scientific evidence for the prevention and control of cardiovascular diseases. Methods: A total of 289 children and adolescents aged 6 to 17 years were included in the study, and weight, height, blood pressure and cIMT were measured. Multivariable Logistic regression model was used to analyze the relationship between obesity and cIMT. Results: The level of cIMT and prevalence of high cIMT in obese males were higher than those in non-obese males(P<0.05), while there was no statistical significance between two weight groups in females (P>0.05). After adjusted for sex, age and blood pressure, compared with the non-obese children and adolescents, the odds ratios (OR s) of obesity for high cIMT in total sample, males and females were 3.03 (95%CI=1.11-8.28), 4.32 (95%CI=1.23-15.21) and 1.45 (95%CI=0.23-9.37) respectively. Conclusion Obesity may increase cIMT levels and risk of high cIMT in children and adolescents. Effective measures should be taken to prevent and control the obesity, and to reduce the risk of abnormal vascular structure in children and adolescents.