Abstract: Composite of magnetic and conductive Hollow polyaniline/CnFe₂O₄ nanosphere with novel core-shell structure were successfully prepared by in-situ polymerization in the presence of ammonium persulfate (APS) as the oxidant and dodecyl benzene sulfonic acid (DBSA) as the surfactant and dopant. The synthesized hollow microsphere composites were characterized by FT-IR and UV/Vis spectrophotometry. X-ray photoelectron spectroscopy was used to determine the degree of coating with a conducting polymer. Its morphology was characterized by scanning electron Microscopy (SEM). The changes of the magnetic properties before and after polyaniline coating were investigated by using vibrating sample magnetometer (VSM).