【Objective】 To explore influencing factors of overweight and obesity among childhood in Guangzhou urban district and to provide useful reference for prevention. 【Method】 Across-sectional survey was carried out among 1844 children and their parents by self-administered questionnaire during 2009. 【Results】 The prevalence rates of overweight and obesity were 11.12% and 7.21%. The prevalence rate of overweight and obesity of boys was higher than girls(χ²=9.849,P<0.05).The birth weights, father BMI and mother BMI of overweight and obesity children were higher than those of control group (t=3.746, 4.610, 4.237, all P<0.001). And the time of having a meal was shorter (t=5.519, P<0.001)than control group. Sex, obesity of parents, the time of having a meal, eating in half an hour before going to bed, whether agree with the opinions "Little physical activity causes obesity" and "Drinking milk everyday was a good habit" were influencing factors of overweight and obesity among children. 【Conclusions】 The results indicate that overweight and obesity among children are quiet common in our city. Overweight and obesity of children are caused by multiple factors, so comprehensive intervention measures should be carried out.