Abstract: In order to explore the effects of different silicon fertilizers on soil arsenic (As) bioavailability and As uptake by rice at different growth stages, field experiments were carried out with silicon fertilizers containing potassium (Si1), calcium and magnesium (Si2), calcium, magnesium and potassium (Si3), calcium, magnesium and iron (Si4) and water-soluble silicon (Si5). At the same application rate of SiO₂ (225 kg/hm²), the As accumulation in rice in the typical stages with corresponding soil As was determined, and the results demonstrated that: (1) The treatments Si4 (including Si, Ca, Mg and Fe) and Si5 (water soluble Si fertilizer) showed higher mitigation ability, decreasing As content in brown rice by 31.3% (P<0.05) and 27.6% (P<0.05), respectively, relative to control. (2) With Si treatment, iron content in root plaques (DCB-Fe) was higher at tillering stage and jointing stages than the control, but not at the filling and mature stages. After silicon application, the As content in iron plaques (DCB-As) decreased continuously throughout the rice growth period, and decreased by 10.0%, 27.0%, 20.0% and 29.5% at the tillering, jointing, filling and ripening stages, respectively. (3) As fractions of non-specifically absorbed, bound to aluminum and residual phase decreased by 15.8%, 9.8% and 10.2%, respectively, while the content of As bound to iron increased by 33.0% in soils with silicon amendments. (4) As accumulation in roots and soil available As had major effects on As unloading into grains at the mature stage, and root As was affected by available silicon in soils. During the whole growth period, As and Fe in the iron plaques had a significant effect on root As uptake. Overall, the application of silicon fertilizers increased the content of soil available silicon and decreased soil available As by increasing the content of As bound to Fe (hydr)oxides, thereby reducing the content of plaque DCB-As and As uptake by rice plants. This research showed that at the same application rate of silicon fertilizers, higher silicon availability or additional iron tended to reduce As accumulation in rice grains.