Abstract: A diagraph of split-root equipment in the soil- solution jointed culture wasused to study the effect of maize/peanut intercroping on Fe(III) reduing capacity ofpeanut root and iron nutrition of peanut. The results showed that Fe[III] reducingcapacity of peanut root in monocropping was much higher than those in intercroppingin 3~9 days after addition insoluble Fe(OH)3. During 9~ 15 days after addtion insolubleFe(OH)3, the Fe(III) reducing capacity of peanut root in monocropping system decreasedquickly and lower than those in intercropping system. The Fe[Ill] reducing capacity ofpeanut root in intercropping not only increased slowly during 6~ 15 days after additioninsoluble Fe(OH)3, but also maintain higher root reducing capacity for longer time. Therewas no great difference of active iron content in young leaves of peanut betweenmonocropping and intercropping system after 3 days addition insoluble Fe(OH)3. After 9days or 15 days addition insoluble Fe(OH)3, the active iron content in young leaves ofpeanut in intercropping were much higher than those of monocropping. The higher rootreducing capacity of peanut in intercropping may play an important role forimprovement iron nutrition of peanut.