The invention relates to the field of centrifugal-process uranium enrichment and particularly discloses a centrifuge cascade entire-section purging method. The centrifuge cascade entire-section purging method comprises the following steps: (1) selecting the diameter of a pore plate; (2) performing air-breaking purging on a section; (3) evacuating the section; and (4) repeatedly performing air-breaking purging and evacuation on the section. The centrifuge cascade entire-section purging method can achieve purging of eight cutoff groups, so that procedures are saved, time is saved and economic loss is reduced; and meanwhile, the centrifuge cascade entire-section purging method can be used for not only purging the whole section and even bigger containers (process levels and units), but also performing building installation in the project construction period, maintenance and replacement in the project running period, even uranium enrichment project decommissioning and the like, and therefore, has a very wide application prospect.