BackgroundEssential trace elements are vital to human health. In this study, our aim was to establish reference intervals of and to evaluate relationships among Ca, Fe, Cu, Mg, and Zn for children. MethodsWe collected blood samples of 3210 children aged 0-14 years from Lu'an, China, and concentrations of the above elements were determined by atomizer absorption spectrophotometer. A nonparametric method was used to establish the reference intervals. ResultsGender-related differences in concentrations were not statistically significant for the elements, except for Fe. There were strong positive and negative correlations between age and Fe (R = 0.305, P < 0.001), Zn (R = 0.573, P < 0.001); and age and Ca (R = -0.372, P < 0.001), Cu (R = -0.127, P < 0.001), respectively. Correlations between Ca-Mg (r = 0.222 similar to 0.384, P < 0.001), Fe-Mg (r = 0.495 similar to 0.614, P < 0.001), and Fe-Zn (r = 0.239 similar to 0.471, P < 0.001) were the strongest compared with others. In multivariable linear regression, after adjusted for confounding factors, the associations between Zn-Fe and Mg-Fe were the strongest with per concentration quintile increase of Fe caused Zn and Mg increasing by 4.19% ( = 0.041; 95% CI: 0.037, 0.045; P < 0.001) and 3.87% ( = 0.038; 95% CI: 0.036, 0.040; P < 0.001), respectively. ConclusionsGender- and age-based reference intervals of Ca, Fe, Cu, Mg, and Zn for children were established, and correlations between them were quite complex. More works are needed to illuminate these relationships and their impacts on children's health.