Disclosed is a method for producing 1,3-butadiene through oxidative dehydrogenation of normal-butene using a parallel reactor in which catalysts are charged into fixed bed reactors and are not physically mixed. More specifically, disclosed is a method for efficiently producing 1,3-butadiene through oxidative dehydrogenation of normal-butene using the parallel reactor containing multi-component bismuth molybdate-based catalysts exhibiting different activities to oxidative dehydrogenation for normal-butene isomers (1-butene, trans-2-butene and cis-2-butene), and butene separated from a C4 mixture containing normal-butene and normal-butane, as a reactant.