Abstract: Objective To prepare the immunomagnetic bead used for cell separation simply and high efficiently.Methods The immunomagnetic beads were prepared by the reaction between the amidos of the antibodies and the carboxyl on the surface of magnetic beads whose carboxyl groups were activated by EDC/NHS.The properties of magnetic beads were studied by dynamic light scattering size analyse,BCA protein quantification assay,flow cytometer and TEM.Results The diameter of the magnetic beads was 110 nm.There were 5214μg CD11a+antibodies lebeled on the per mg magnetic beads.FACS results indicated that KG21a cell were separated efficiently by the immunomagnetic beads.TEM results indicated that the immunomagnetic beads were combined on the surface of the cell.The cultivation and microscopic observation indicated that the immunomagnetic beads didn't affect the activation of the cell.Conclusion The new kind immunomagnetic beads which could be used for cell separation without negative effect on cell's activation is prepared successfully.