The effects of the initial Cd²⁺ concentration, soil pH, organic matter, texture and Bacillus subtilis-biochar complex on the Cd²⁺ adsorption in soils were studied by adsorption and desorption experiments. The results showed that the adsorption capacity of soil for Cd²⁺ increased with the increase of Cd²⁺ initial concentration and pH. Organic matter significantly promoted the immobilization of Cd²⁺ in soil. The adsorption capacity of loam for Cd²⁺ was significantly higher than that of sandy loam. After applied Bacillus subtilis-biochar immobilized complex, the adsorption capacity of soil for Cd²⁺ was significantly higher than that of the control group, and the maximum increase was 11.7% when applied 20 ml/kg of Bacillus subtilis-biochar immobilized complex. The Freundlich model could well fit the adsorption process of Cd²⁺ (R²=0.997). The desorption rate of Cd²⁺ in soil after applied Bacillus subtilis-biochar immobilized complex was lower than that of the control group. In conclusion, the application of Bacillus subtilis-biochar immobilized complex in soil can effectively fix Cd and has a great potential as a passivating agent to repair soil polluted by heavy metals and ensure the safety of food and vegetables.