Sophora tonkinensis Gagnep., whose roots and rhizomes are used as traditional Chinese medicine, are cultivated widely in China. However, cadmium pollution in soil can lead to the excessive accumulation of cadmium (Cd) in Sophora plants, reducing its production. Applications of mixtures of biochar and organic fertilizers were expected to improve the overall health of Cd-contaminated soil and increase Sophora yield and quality. Nevertheless, the potential biological mechanisms of the interaction between this fertilization technique and soil microorganisms are still uncovered. This study aimed to investigate the restorative impact of combined effects of biochar and organic fertilizer (the OC treatment, with a biochar to organic fertilizer ratio of 1:2) applications on the growth of Sophora plants in Cd-contamined soil. The results indicated that this soil remediation method significantly reduced the Cd content