The present invention relates to a method for separating and purifying 1-butene from raffinate-2 stream at high purity and a high yield, the method comprising the steps of: supplying raffinate-2 including n-butane, isobutane and 1-butene to a first distillation column to obtain heavy raffinate-3 including n-butane from the lower part of the first distillation column and recovering an upper fraction including 1-butene from the upper part thereof; and supplying the upper fraction including 1-butene into a second distillation column to recover a first lower fraction, enriched with 1-butene, fromthe lower part of the second column and recovering light raffinate-3 including isobutene from the upper part thereof, wherein the heat of the upper fraction recovered from the upper part of the firstdistillation column is supplied to the lower part of the second distillation column through a first heat exchanger, and 1-butene at high purity and high yield can be recovered while an energy recoveryamount is maximized by means of a double effect distillation.