The invention belongs to the field of rare cell and particle enriched screening and relates to a spiral microchannel, and a use method and a tandem and parallel mounting method thereof. For the technical problem of the spiral microchannel in the field of sorting and enrichment of peripheral blood circulating tumor cells of patients suffering from malignant tumor, a tandem and parallel type spiralmicrochannel inertial separation structure capable of performing cascade application of a plurality of spiral microchannels reasonably is cleverly designed; and relative to the existing similar technologies, the tandem and parallel mounting method has the following advantages: high circulating tumor cell capturing efficiency and treatment flux on sorting and enrichment of the peripheral blood circulating tumor cells are achieved, the purity of the circulating tumor cells can be maximized, the loss of the circulating tumor cells can be minimized, the original phenotype of the circulating tumorcells is maintained, the obtained cell suspending liquid containing the high-purity circulating tumor cells is particularly suitable for subsequent biomedicine detection, genetic analysis, cell culture, xenograft tumor preparation and the like, and wide and far-reaching clinical actual application value is achieved.