Objective:To study the effect of multi-micronutrients supplementation on nutritional status of children. Method:220 students aged 8-12 years were observed for 6 months and 1 year follow-up. A half of them was given the supplements, another half as placebo. Results:In comparison with the placebo, the supplemented children had a higher urine excretion of vitamin B2 and vitamin C after loading; a higher concentration of serum 1.25(OH)2D3, hydroxyproline and hydroxyproline/creatinine ratio in fasting urine, and a higher bone mineral content and bone mass density in mid-ulna. The supplemented children performed significantly better than the placebo in reading speed, learning capacity and arithmetic examinations. After one year there was still significant difference between intervention and control group in hemoglobin content and marginal vitamin A deficiency. Conclusion:The micronutrients supplementation played a notable rule in resulting better nutritional status and learning ability of school children, and intervention would have a long effect on their health and nutritional status.