This study was conducted to find out reasonable soil management strategy using amendments such as phosphate (P) and oyster shell fertilizer for reducing soil cadmium (Cd) extractability and radish Cd uptake in two arable soils and determine the reaction mechanism of Cd immobilization in phosphate or oyster shell amended soils. Fused and super phosphate (FSP) and K2HPO4, were applied at a rate of 0, 33.5, 100.5, and 167.5 kg P ha-1 and oyster shell and Ca(OH)2 were applied at a rate of 0, 2, 4, and 8 Mg Ca ha-1 before radish (Raphanus sativa L.) seeding in Cd contaminated arable soils. Plant available Cd concentration in soil and Cd concentration in radish increased with increasing FSP application, but decreased with K2HPO4. The significant decrease in soil pH and negative charge of soil by FSP application led to an increase in plant available Cd in soil and in Cd uptake in radish. However, K2HPO4 increased soil pH and negative charge of soil and decreased plant available Cd. Soil pH and negative charge of soil showed significant negative relationships with Cd concentration in harvested radish, implying that these two factors played an important role in controlling Cd uptake by radish in phosphate-applied soil system. Oyster shell was less effective at increasing soil pH and net negative charge than Ca(OH)2, but more effective at suppressing radish Cd uptake in both roots and shoots. The portion of Cd that is strongly bound to soil (fraction 5) increased more with oyster shell than with Ca(OH)2. Radish plant Cd concentration was positively correlated with 0.1 N HClextractable Cd and negatively correlated with the residual Cd fraction (F5), indicating that an increase in the strongly bound Cd fraction played an important role in reducing radish Cd uptake in soil to which oyster shell was applied. The greater potential of oyster shell to decrease Cd extractability in soil and plant Cd uptake compared to Ca(OH)2 might be attributed to the layered morphology of oyster shells. Based on these results, K2HPO4 and Oyster shell could be good soil amendments to reduce Cd phytoavailability in contaminated arable soil.