【Objective】 To study the prevalence and influencing factors of simple obesity among preschool children in Shajing street,Baoan district,Shenzhen . 【Method】 Cluster sampling method was used to analyze the physical examination data of Shajing street form 2006 to 2010, further investigation of the parents of obese children to filter the factors of childhood obesity. 【Results】 Obesity in preschool children from 2006 to 2010 were 6.29%,6.42%,7.00%,7.26%,7.58%, respectively,and showed an increasing trend (P= 0.001);The prevalence of obesity showed an increasing trend in pre-school boys, girls, 5 to 6 years of age group. (P<0.05). Logistic regression analysis showed that heavier birth weight, love to eat sweets, regular intake of high fat and calorie foods, outdoor exercise less, the more the lack of nutritional knowledge of parents of children with simple obesity rate. 【Conclusion】 There has a rapid rise in the prevalence of obesity pre-school children in Baoan district, and need for timely control.