The iron (Fe) redox cycle exhibits a unique role in controlling the Cd bioavailability in the soil-rice system. An amendment developed independently was selected and a field experiment was carried out to investigate the Cd transportation from the rhizosphere soil to the Fe plaque and further to different rice tissues at four different growth stages and to highlight some possible mechanisms by which the Fe redox cycle controlled the Cd bioavailability in the rice paddy field. The results showed that the amendment induced the formation of Fe sulfides, which co-precipitated with Cd reducing the NH₄Ac-extractable Cd contents in rhizosphere soils at the tillering, jointing and filling stages; the oxidation of Fe sulfides increased the NH₄Ac-extractable Cd content in the rhizosphere soil at the maturing stage; the formation of Fe sulfides in rhizosphere soils impeded the migration of Fe(II) from the rhizosphere soil to the root surface, decreasing contents of DCB-extractable Fe and Cd in Fe plaques at the tillering and filling stages; the Fe redox cycle controlling the Cd activity in rhizosphere environment decreased the distribution proportion of Cd in the rice grain at the maturing stage. The exploration of practical remediation strategies for Cd from the perspective of Fe redox cycle may be promising.