The present invention provides a process for producing butadiene by oxidative dehydrogenation of butylene, comprising: a reaction stage, wherein a multi-stage adiabatic fixed bed in series is used, wherein butylene, oxygen-comprising gas and water are reacted in the presence of a catalyst in each stage of the adiabatic fixed bed with the first stage of the adiabatic fixed bed being further separately fed a diluent, being nitrogen and/or carbon dioxide, and the molar ratio between this separately fed diluents and the oxygen of all the oxygen-comprising gases fed in the subsequent stage(s) of the adiabatic fixed bed being controlled, wherein the oxygen-comprising gas is air, oxygen-enriched air or oxygen, and at least one of all the oxygen-comprising gases fed in the subsequent stage(s) of the adiabatic fixed bed is oxygen-enriched air having a specific oxygen concentration or oxygen; and a post treatment stage, wherein the effluent from the last stage of the adiabatic fixed bed is treated to obtain a product butadiene. The present invention has an advantage that the whole process is with reduced total energy consumption.