The effects of in-situ immobilization of heavy metals by applying natural and chitosan-introduced zeolite, bentonite, and activated carbon (AC) were systematically studied to remediate cadmium (Cd)-contaminated soils in a pot experiment using Brassica juncea as the indicator plant. The results show that zeolite, bentonite, and its chitosan composites can increase soil pH and reduce the biological effectiveness of heavy metals. The Brassica juncea dry weight increased with increasing of amendment dosage. Highest values were found for CS-AC, followed by CS-bentonite, CS-zeolite, AC, bentonite, and zeolite. With an amendment dosage of 75 g per pot, Brassica juncea dry weight increased by 41.91%, 39.00%, 27.64%, 35.93%, 23.78%, and 23.58%, respectively, for CS-AC, CS-bentonite, CS-zeolite, AC, bentonite, and zeolite, compared to the control. Cadmium uptake by Brassica juncea was lowest for this dosage. With a dosage of 75 g, 50 g, 75 g, 75 g, 50 g, and 75 g per pot for CS-AC, CS-bentonite, CS-zeolite, AC, bentonite, and zeolite, respectively, Cd uptake decreased by 21.89%, 19.88%, 19.48%, 18.67%, 17.47%, and 13.85%, respectively. Similarly, bioavailable Cd content decreased by 27.38%, 19.29%, 22.83%, 23.22%, 15.74%, and 8.66%, respectively, compared to the control.