Objective To investigate the bone mineral density of children aged 3~6 years in Zhongguancun, Beijing, and to explore the related factors influencing bone development.Methods A total of 357 children aged 3~6 years in 5 public kindergartens in Zhongguancun area were examined by quantitive ultrasound bone mineral density after their parents′ consent, and the basic demographic information, environment, diet and other factors were collected by self-made questionnaire. The above factors were screened by t test or variance analysis, and the degree of action of influencing factors on bone mineral density was judged by linear regression analysis.Results The detection rate of bone mineral density deficiency in children aged 3~6 years was 12.0%, and the prevalence of bone mineral density in boys (7.1%) was lower than that in girls (18.2%). With the increase of age, the bone mineral density Z score of children decreased gradually. The higher the weight for age evaluation of children, the lower the Z score of bone mineral density in children, the difference was statistically significant. The effect of influencing factors on bone mineral density was:age > gender > weight for age > duration of sunshine.Conclusion The prevalence of bone mineral density is low in children aged 3~6 years in Zhongguancun area. Maintaining a good lifestyle and reasonable diet and having the right weight are important for bone mass accumulation and bone mineral density enhancement in children.