We deal with the preparation of NiMgZnFeⅢ-SO4 layered double hydroxides (LDHs) with the layered precursor method and introduce excessive ZnO into the NiMgZnFeⅢ-SO4 LDHs to produce NixMgyZn1-x-yFe2O4 ferrites that contain massive ZnO.Then the NixMgyZn1-x-yFe2O4 ferrites are treated with NaOH solution to remove ZnO to produce the porous NixMgyZn1-x-yFe2O4 magnetic material:when y =0,porous NiZnFe2O4 ferrite magnetic materials are obtained;when y ≠ 0,porous NiMgZnFe2O4 ferrite magnetic materials are obtained.From analyses of these two ferrites,their pore-forming mechanism and comparison of their properties before and after they undergo the alkali treatment,we find that after being treated by the NaOH solution,NiZnFe2O4/NiMgZnFe2O4 have better uniform-structure pores,which will greatly expand their pore volume,widen their application scope and improve their magnetic properties.Owing to their fine resistance,high Curie temperature,low temperature coefficient and good high-frequency performance,nickel-zinc ferrite materials have been widely used in high-frequency magnetic recording fields such as video cassette recorders (VCRs),hard disk machines and floppy disc drives,where high-density magnetic recording is required.[1-3] Recently,nickel-zinc ferrite materials have also begun to be used as magnetic carriers for the immobilized enzyme because they can control the movement of the magnetic immobilized enzyme through the exteal magnetic field and cause it to be separated and easily recovered from the reaction system.[4-7]