A device for preparing octanol, comprising: a distillation column provided with a condenser, a reboiler, a heat exchanger configured to produce steam for column top stream, a heat exchanger configured to preheat a raw material, and a divided wall, wherein the distillation column is divided into a raw material feed region, a product outflow region, a column top region, and a column bottom region, a raw material comprising octanol flows into the raw material feed region, and the raw material flowing into the raw material feed region is separated into a product stream, a column bottom stream and a column top stream to flow out therefrom, the column bottom stream flows out from the column bottom region, and some of the column bottom stream are refluxed to the distillation column through the reboiler, the column top stream flows out from the column top region and passes through the condenser, and some of the column top stream passing through the condenser are refluxed to the distillation column, the product stream flows out from the product outflow region, wherein the heat exchanger configured to produce steam for column top stream is arranged in a front stage of the condenser and configured such that some or all of the column top stream flowing out from the column top region exchanges heat with water to produce steam, and wherein the heat exchanger configured to preheat a raw material is arranged in a front stage of the raw material feed region and configured such that some or all of the product stream flowing out from the product outflow region exchanges heat with the raw material flowing into the raw material feed region to heat the raw material or the heat exchanger configured to preheat a raw material is arranged in a front stage of the raw material feed region and configured such that some or all of the column bottom stream flowing out from the column bottom region exchanges heat with the raw material flowing into the raw material feed region to heat the raw material. a distillation column provided with a condenser, a reboiler, a heat exchanger configured to produce steam for column top stream, a heat exchanger configured to preheat a raw material, and a divided wall, wherein the distillation column is divided into a raw material feed region, a product outflow region, a column top region, and a column bottom region, a raw material comprising octanol flows into the raw material feed region, and the raw material flowing into the raw material feed region is separated into a product stream, a column bottom stream and a column top stream to flow out therefrom, the column bottom stream flows out from the column bottom region, and some of the column bottom stream are refluxed to the distillation column through the reboiler, the column top stream flows out from the column top region and passes through the condenser, and some of the column top stream passing through the condenser are refluxed to the distillation column, the product stream flows out from the product outflow region, wherein the heat exchanger configured to produce steam for column top stream is arranged in a front stage of the condenser and configured such that some or all of the column top stream flowing out from the column top region exchanges heat with water to produce steam, and wherein the heat exchanger configured to preheat a raw material is arranged in a front stage of the raw material feed region and configured such that some or all of the product stream flowing out from the product outflow region exchanges heat with the raw material flowing into the raw material feed region to heat the raw material or the heat exchanger configured to preheat a raw material is arranged in a front stage of the raw material feed region and configured such that some or all of the column bottom stream flowing out from the column bottom region exchanges heat with the raw material flowing into the raw material feed region to heat the raw material.