The invention relates to the field of production of 2-butene from butane and discloses a method and a device for producing 2-butene from butane. The method comprises the following steps: (1) carryingout dehydrogenation reaction on butane so as to obtain a dehydrogenation product; (2) contacting the dehydrogenation product with maleic anhydride, and carrying out copolymerization reaction between terminal olefins of C4 or less in the dehydrogenation product and maleic anhydride; (3) performing gas-liquid separation on the product obtained in the step (2) so as to obtain a gaseous product and aliquid-solid mixture; (4) performing gas phase separation on the gaseous product obtained in the step (3) so as to obtain 2-butene, and returning the obtained butane serving as a cycle stock to the step (1); and (5) separating the liquid-solid mixture obtained in the step (3), thereby obtaining the solid product, namely a polymer containing the maleic anhydride functional group. The operation of producing 2-butene from butane and co-producing the polymer containing the maleic anhydride functional group can be realized, and the copolymer can serve as the raw material of the functional material.