The effects of modified biofuel ash (BFA), lime (CaO and CaCO₃), rice biochar (BC), FeSO₄ and Fe on the effect of passivation remediation and Cd migration in soil-rice system of Cd-contaminated paddy soils were comparatively investigated through in situ remediation treatment trials. The results showed that the six passivation material treatments had a range of 0.519 to 6.25 mg·kg^-1 (-5.31% to 14.5%) and 0.290 to 0.330 mg·kg^-1 (-3.13% to 12.5%) on the reduction rate of total Cd and effective state Cd in soil, respectively, but there was no significant differences between treatments. CaO and CaCO₃ treatments at application rates of 200 to 600 kg·acre^-1 could raise soil pH by 0.38 to 0.80 and 0.25 to 0.48 units, respectively, and application of modified power plant ash could raise soil pH by 0.21 to 0.28 units, while biomass char and iron powder treatments had no significant effect on soil pH. Compared with the control, the six materials could increase the rice yield by -6.20% to 32.2% and reduce the seed Cd content by 3.35% to 61.0%, with the 400 kg·acre^-1 CaO, 600 kg·acre^-1 FeSO₄, and 600 kg·acre^-1 BFA treatments having the greatest reduction by 61.02%, 55.4%, 44.2% respectively. In the soil-rice system, the enrichment of Cd in different parts of rice showed that root > stem > seed , where 400 kg·acre^-1 CaO, 600 kg·acre^-1 FeSO₄, and 600 kg·acre^-1 BFA treatments could reduce the enrichment coefficient of Cd in all parts of rice.