Objective To analyze the rate of erythrocyte iron incorporation and provided guidance for the iron nutrition for prepubertal children. Methods Fifty-seven prepubertal children of Beijing were involved in this study and each subject was orally administered 3 mg of 57Fe twice daily to obtain a total of 30 mg 57Fe after a 5-d period. The stable isotope ratios in RBCs were determined in 14th day, 28th day, 60th day, and 90th day. The erythrocyte incorporation rate in children was calculated using the stable isotope ratios, blood volume and body iron mass. Results The percentage of erythrocyte 57Fe incorporation increased starting 14 th day, reached a peak at 60 d (boys: 19.67% ± 0.56%, girls: 21.33% ± 0.59%) and then decreased. The erythrocyte incorporation rates of 57Fe obtained for girls in 60th day was significantly higher than those obtained for boys (P < 0.0001). Conclusions The oral administration of 57Fe to children can be used to obtain erythrocyte iron incorporation within 90 d. Prepubertal girls should begin to increase the intake of iron and further studies should pay more attention to the iron status in prepubertal children.