The invention provides a method for preparing magnetic ferroferric oxide/conductive polyaniline light-weight composite hollow microspheres, which relates to a method for preparing a magnetic ferroferric oxide/conductive polyaniline composite material. The invention solves the problems of high density and easy agglomeration of the traditional magnetic nanometer particle/conductive polymer composite material. The method comprises the following steps of: regulating ferrous chloride and ferric chloride solutions to be alkaline, adding sodium dodecyl benzene sulfonate and reacting to obtain ferroferric oxide; and modifying hollow glass microspheres by using poly(diallyldimethylammonium chloride) solutions after alkaline cleaning, then reacting the hollow glass microspheres with the ferroferricoxide, sequentially immersing obtained solid particles by using the poly(diallyldimethylammonium chloride) solutions and polystyrene sulfonic acid solutions, then adding the solid particles to aniline solutions, initiating polymerization by using ammonium persulfate, and washing and drying the solid particles to obtain the composite hollow microspheres. The composite hollow microspheres have bothconductivity and magnetism, the density is 0.78-0.8g/cm<3>, and the composite hollow microspheres are not easy to agglomerate and are used for fields of military equipment stealth technology and civil anti-electromagnetic radiation.