An immunomagnetic composition, a preparation method and a usethereof, and a kit for treating a cancer. The immunomagnetic compositioncomprises a core layer, a shell layer and an outer layer. The shell layer iscomposed of a composite and encapsulates the core layer. The composite isformed by the combination of fucoidan, oxidized dextran, and a plurality ofsuperparamagnetic iron oxide nanoparticles by hydrophobic interaction. Theouter layer comprises at least one antibody.
