Objective To study the prevalence of overweight and obesity among primary school students in Kai fu District in Changsha and provide the scientific evidence for prevention and control of obesity in students.Method 4140 students aged 7 to 12 years in Kaifu District in Changsha were randomly selected,and overweight and obesity was assessed by the method of body mass index(BMI). Results The prevalence rates of overweight and obesity were 9.76% and 7.39%.Among the males and females,the rates were 12.31% and 6.84% for overweight while 9.37% and 5.13% for obesity,respectively.The rates of overweight and obesity for males were higher than those for females.Conclusion The prevalence of overweight and obesity among pupils is at a high level and higher prevalence rate is found in the boys.It is important to develop early measures to prevent and control childhood overweight and obesity.