Abstract: The effects of the iron nutrition on nodule development and nitrogenfixing functions of peanut were studied in nutrient solution culture experiment. The major findings were summarized as follows: In nutrient solution culture with a supply of 80mol/L Fe (EDTAFe ), the N content and N uptake of peanut shoot have increased by 2.0 % and 11.7% as compared with control, respectively. The results showed that iron was involved in nitrogenfixing process directly. When the supply of EDTAFe was of the range of 0～80mol/L, iron had great effects on excisable nodule, nodule dry weight and nitrogenase activity, but had no effect on number of nodule initials. The excisable nodule number and nodule dry weight had increased by 194% and 87% as compared with control, respectively, and the nitrogenase activity of per plant and special nitrogenase activity of peanut had increased 126% and 10%. The results showed that iron nutrition had important effects on nodule development first, and then had great effects on nitrogenfixation functions of peanut nodule.