Disclosed are a ferrite catalyst, its preparation method and use. The catalyst has a formula of FeAaDbOc, wherein A is Mg atom, Zn atom or a mixture of these two atoms in any ratio; D is one or more atoms elected from the group consisting of Ni, Co, Mn, Ca, Mo or V; a=0.01˜0.6; b=0˜0.30; c is a number satisfying the valence. The catalyst is prepared by a method comprising mixing the metal oxide precursors according to the chemical ratios and grinding by ball milling to obtain the ferrite catalyst. The catalyst exhibits excellent activity and selectivity when used in a reaction for preparing butadiene by oxidative dehydrogenation of butene. The preparation of the catalyst is simple, controllable and well repeatable, with reduced waste water and waste gas during preparation.