Purpose <p> Iron-bound phosphorus (P), a major form of P, plays a crucial role in the migration and transformation of P at the sediment–water interface.&#xa0;</p> Methods <p> To elucidate the relationship between iron-cycling microorganisms and the release of P from iron (Fe) oxides, a pure culture system was established to examine the regulatory effects of Fe-reducing bacteria,<i>Shewanella oneidensis </i>MR-1, on the release of hematite-bound P.&#xa0;</p> Results <p>Laboratory experiments conducted under anoxic conditions demonstrated that microbial activity significantly enhanced hematite dissolution and reductive Fe release compared with abiotic controls. This process, driven by the bacterial reduction of Fe(III) to Fe(II), resulted in the simultaneous release of adsorbed P. The maximum phosphate (PO₄^3-) concentration in the bacterial treatment reached 8.99 ± 0.22 mg L^-1, significantly higher than that in the CK group. X-ray photoelectron spectroscopy analysis revealed a distinct increase in surface Fe(II) content (from 9% to 15%) in the microbial treatment, whereas no significant change was observed in the CK group (from 8% to 10%), indicating mineral transformation. Redox-active mediators secreted by <i>Shewanella oneidensis</i> MR-1, and electron transport system activity further demonstrated that <i>Shewanella</i><i> oneidensis</i> MR-1 facilitated extracellular electron transfer, thereby accelerating Fe reduction and promoting the P mobilisation.&#xa0;</p> Conclusion <p><i>Shewanella oneidensis</i> MR-1 promoted hematite dissolution through dissimilatory Fe(III) reduction, increasing surface Fe(II) proportion. Cytochromes and riboflavin served as key electron shuttles, confirming that extracellular electron transfer directly couples Fe(III) reduction to P mobilization from crystalline hematite.&#xa0;</p>