Abstract: Objective To investigate serum 25-hydroxyvitamin D 25(OH) D levels of primary school children in Zhongyuan District of Zhengzhou,and explore the factors influencing vitamin D level.Methods A multi-stage stratified cluster random sampling method was performed to enroll 1000 primary school children in Zhongyuan District of Zhengzhou as study objects.All children were tested for serum 25(OH) D level.The levels of vitamin D in children with different age,gender and body mass were compared.The influencing factors of vitamin D level were analyzed by multivariate Logistic regression analysis.Results In the 1000 children,mean value of serum 25(OH) D level was(70.15±8.96) nmol/L.The proportion of vitamin D insufficiency was the highest(56.20%),followed by vitamin D sufficiency,accounted for 30.30%.The proportion of vitamin D deficiency was the lowest(13.50%).The levels of serum 25(OH) D in children aged 6-9 years old were significantly higher than those in children aged 10-12 years old(P<0.05).The number of children aged 6-9 years old with vitamin D deficiency or insufficiency was significantly less than that of children aged 10-12 years old(66.98% vs 74.52%)(P<0.05).The levels of serum 25(OH) D in boys were significantly higher than those in girls(P<0.05).The number of boys with vitamin D deficiency or insufficiency was significantly less than that of girls(66.82% vs 75.22%)(P<0.05).The levels of serum 25(OH) D in the normal weight children were significantly higher than those in the overweight children and the obese children(P<0.05).The levels of serum 25(OH) D in the overweight children were significantly higher than those in the obese children(P<0.05).The number of the normal weight children with vitamin D deficiency or insufficiency was significantly less than that of the overweight children and the obese children(P<0.05).The number of the overweight children with vitamin D deficiency or insufficiency was significantly less than of the obese children(P<0.05).The results of multivariate Logistic regression analysis showed that BMI,age,sunlight radiation and diet were the important influencing factors for vitamin D level.Conclusion There is vitamin D deficiency or insufficiency in some primary school children in Zhongyuan District of Zhengzhou.Relevant workers should be paid attention to.The vitamin D supplementation for children should be strengthened.