By selecting the red paddy soil，taking the chitosan (modified)-zeolite (N-methylene chitosan hypophosphate-zeolite (ZHC), N-methylene chitosan phosphite-zeolite (ZPC)) as passivation agent and considering the factors of different processing time and amount of passivator added, the effect of chitosan (modified)-zeolite on passivation of Cd in soil was compared and analyzed. The results showed that pH value of soil could effectively increase by using the both passivants. The content of Cd in acid extractable in paddy soil reduced obviously. The passivating effect of passivating agent increased significantly with the passage of time. By comparing different types and different doses of passivation agents, the best passivation effect was that the additive amount was 3.2% ZHC. Using toxicity characteristic leaching procedure (TCLP) extraction, the concentration of heavy metals in red paddy soil decreased by 48.9%.