【Objective】 To provide scientific reference for children obesity prevention and control, the relationship between birth weight and overweight or obesity in childhood was explored. 【Methods】 A historical cohort study was carried out by using questionnaire and physical examination. Subjects were randomly selected from a birth cohort including 1435 couples of high and normal birth weight babies in Wuxi. The relationship between birth weight and overweight or obesity in childhood was analyzed by collecting the information associated with obesity. 【Results】 The incidences of overweight and obesity were 13.10% and 2.86% in high birth weight babies and those in normal birth weight babies were 9.69% and 1.61%. The incidence of overweight and obesity of high birth weight babies was much higher than that of normal birth weight babies(P <0.01). Compared with normal birth weight babies, the relative risks of overweight and obesity among high birth weight babies were 1.35 and 1.78 respectively. The attributable risks of those were 3.41% and 1.26% respectively. The trend χ² test indicated the incidences of overweight and obesity increased with increasing birth weight (P<0.01), the RR and AR of overweight and obesity also increased. The results of multiple linear regression analysis indicated birth weight, gender, BMI of father and mother, preference for eat fried foods might be risk factors of BMI in childhood. 【Conclusion】 Children obesity could be affected by high birth weight and the obesity prevention should begin from prenatal period.