The invention relates to an extraction structure and extraction method for a rectifying tower. The extraction structure comprises a plurality of rectifying-tower-top extraction pipelines, oil-water separators arranged at the tail ends of the rectifying-tower-top extraction pipelines and a plurality of metering grooves and intermediate grooves connected with the rectifying-tower-top extraction pipelines and the oil-water separators through pipelines, wherein the rectifying-tower-top extraction pipelines can be connected with the intermediate grooves or primary and secondary metering grooves with or without the help of the oil-water separators; the oil-water separators can be separately communicated with the primary and secondary metering grooves; and the primary metering grooves can be separately communicated with the secondary metering grooves. A rectifying-tower-top fraction can be extracted to one or more designated metering grooves, intermediate grooves or reaction vessels, so the process of fraction collection is more flexible and precise. Compared with the prior art, the extraction structure and extraction method provided by the invention have the advantages that 1) a faction can be directly extracted to the intermediate groove when a single vessel is used for production; 2) a fraction extracted from any tower can enter a designated metering groove when multiple towers are used for production; and 3) when an extraction amount is small, the fraction directly enters the metering grooves without passing through the oil-water separators.