A numerical-control machine-tool rectilinear motion shaft geometry precision rapid detection method belongs to the numerical-control machine-tool detection technology field. The method is characterized by firstly, installing a measurement device on a rectilinear motion shaft, carrying out uniform motion at three different speeds along with the rectilinear motion shaft, and carrying out multichannel acquisition automatically and storing motion measurement point acceleration data by an upper layer measurement system; then, based on a condition that a same geometric error signal can be decomposedinto different frequency components, filtering acceleration signals under different measurement speeds; and finally, carrying out time-domain quadratic integral on each filtered acceleration data andacquiring displacement data, carrying out data superposition on the displacement data under three kinds of measurement speeds till that rectilinear motion shaft deformation calculation is completed;and through an endpoint line connection method, calculating the linearity of a rectilinear motion shaft, and completing the rapid linearity measurement of the machine tool rectilinear motion shaft. The method has advantages that debugging is convenient; measurement efficiency is high; and data processing capability is good. The rapid measurement of the geometric accuracy of machine-tool rectilinear motion shaft can be realized, an equipment integration level is high and automation can be conveniently realized.