With the rapid development of modern industry，soil heavy metal pollution has become a critical issue in global environmental governance. The widely distributed calcareous soil in northern China is also confronted with this challenge. Among numerous remediation techniques，in-situ passivation is recognized as one of the most effective methods for reducing the bioavailability of heavy metals in soil. To investigate the effects of different passivating agents on the remediation of heavy metal-contaminated calcareous soil，this study used Cd-contaminated calcareous soil as the study subject. Chinensis (Chinese cabbage) as the test crop, through indoor pot experiments，six passivators—fly ash，sepiolite，ferric oxide，manganese oxide，biochar，and bentonite—were applied at concentrations of 1% and 3% (w/w)，respectively，to evaluate their passivation effects on soil Cd and impactson plant growth. The results showed that compared with the control，additions of fly ash，sepiolite，and biochar increased plant fresh weight by 2%-20.8%. Biochar，fly ash significantly improved plant dry weight. The SPAD values of Chinese cabbage leaves treated with different passivators was increased by 0.58%-5.8%，compared to the control，but the differences did not reach statistical significance. After passivator application，soil pH values exhibited an upward trend. Biochar significantly increased soil organic matter content，with a maximum increase of 44.5% relative to the control. Under the 1% application rate，fly ash，sepiolite，biochar，and bentonite reduced soil exchangeable Cd content by 3.4%，11.6%，19.4%，and 14.2%，respectively；at the 3% rate，these reductions were 7.3%，11.5%，23.8%，and 16.4%. Additionally，no significant variations were detected in the contents of iron-manganese oxide-bound and organic matter-bound Cd fractions，while the proportion of residual Cd showed an upward trend across most treatments. Passivator additions effectively reduced plant Cd accumulation，with aboveground Cd contents decreasing by 11.2%-21.4% and underground Cd contents decreasing by 1.2%-16.3%，compared to the control. Overall，fly ash，sepiolite，biochar，and bentonite demonstrated superior passivation effects on Cd pollution in calcareous soils，while ferric oxide and manganese oxide showed limited efficacy under the tested conditions. These findings provided a scientific basis for the targeted selection of passivators in the remediation of heavy metal pollution in calcareous soils of northern China.