Abstract: In this thesis, using Fe3O4 as magnetic source and chitosan as polymer, magnetic chitosan composite microparticles (Fe3O4 /CS) were prepared by coagulating precipitation.The magnetic Fe3O4 /CS microparticles were charectered by IR, VSM, and the size distribution of magnetic Fe3O4 /CS was tested.Using the magnetic Fe3O4/CS microparticles as carrier, superoxide dismutase (SOD) was immobilized by chemical cross-Linking.Effect of the amount of SOD, time, pH and the amount of glutaraldehyde on the activity of immobilized SOD were studied.The optimum immobilization conditions of SOD were also studied by orthogonal experiment.The optimum immobilization conditions were as follows:the amount of SOD was 100mg per 200mg magnetic chitosan microspheres, the time was 240min, the pH was 6.5 and the amount of glutaraldehyde was 0.20mL.After using four times, the activity and recovery rate of immobilized SOD were 376U/g and 56.5% respectively, which showed that the immobilized SOD had good reusability.