Objective To investigate 25-hydroxy vitamin D [25(OH)D] levels of healthy children in Taizhou by testing serum 25(OH)D of some children,and provide evidence for rickets. Methods A total of 476 children were enrolled in children healthcare outpatient clinic of Taizhou from October 2013 to September 2014.The blood samples were colleted on an empty stomach in the morning,and the serum 25(OH)D levels were detected by tandem mass spectrometry. Results The levels of 25(OH)D in serum of all age groups of children in Taizhou city were skewed distribution,with the median of that,as infant group,early childhood group,preschool group,school age group,respectively.After the rank sum test,the difference of vitamin D levels in different age groups was statistically significant (P<0.05).While there were no significant differences in the level of vitamin D in different age groups between boys and girls (P>0.05).476 children,a serious lack of vitamin D(≤5 ng/ml) (15/476) accounted for 3.15%;The lack (≤15 ng/ml) accounted for 38.45% (183/476);Under or below(15～20 ng/ml)accounted for 17.86% (85/476);Adequate (>20 ng/ml) accounted for 40.55% (193/467);Excess (>100 ng/ml) accounted 0.Vitamin D deficiency (≤20 ng/ml) children accounted for 59.45% (283/476),the infant group was 9.3% (8/476);Child group was 36.21% (42/467);preschool group was 70.13% (54/567);school age group was 90.86% (179/476),they were mainly school age children.There were significant differences among all groups (P<0.05) and statistically significant differences in serum vitamin D levels in different seasons (P<0.05). Conclusions The vitamin D levels of chinldren in Taizhou decreased with age,the lack of vitamin D in school age children is particularly serious.Therefore,children over the age of 3 need vitamin D supplementation,especially in winter.