Abstract:Abstract: [Objective] We studied the effects of arbuscular mycorrhizal (AM) fungus (Glomus versiforme) on iron species at different trifoliate orange [Poncirus trifoliata (L.) Raf.] rhizospheric soil with pot culture. [Methods] The soil range in horizon was separated into 0-2 cm, 2-4 cm and 4-8 cm away from the citrus taproot by nylon bags with 32 μm sieve, which citrus roots could not across but AM hyphae could. Mycorrhizal colonization was testified by trypan blue staining method. Iron species contents were quantified by atomic spectrometry, and phosphorus contents was through phospho-vanado- molybdate colorimetry. [Results] Available iron contents in AM treatment were followed the order by 0-2 cm > 2-4 cm > 4-8 cm. AM fungus decreased the contents of Exch-Fe, OM-Fe, RES-Fe. The concentration of Exch-Fe, Carb-Fe and MnOX-Fe became zero one year later. AM colonization was significantly positive relation with RES-Fe (P<0.01) [Conclusion] Arbuscular mycorrhizal fungi could affect the activation on mineral elements, and improve the available iron contents through the changes on iron species in soil.