The invention belongs to the technical field of the synthetic aperture radar imaging technology, and particularly relates to an imaging method for an acceleratedly factorized back-projection bunching synthetic aperture radar. The imaging method for the acceleratedly factorized back-projection bunching synthetic aperture radar includes the following steps that platform motion is used for forming a synthetic aperture, the center of the aperture is used as the original point to build a polar coordinate system (r, theta), and the whole aperture is divided into N0 isometric sub-apertures; it is set that alpha is equal to sin theta, and an impulse response function of a pixel point at the position of (rp, theta) corresponding to the uth sub-aperture is expressed as I (u) (alpha)=I (u) (rp, alpha); a two-dimensional wave number variable is defined; a two-dimensional wave number spectrum corresponding to the uth sub-aperture is obtained; according to two-dimensional wave number spectra corresponding to distance wave numbers, two-dimensional wave number spectra corresponding to all the sub-apertures are spliced in the azimuth direction, and one-dimensional wave number spectra corresponding to the distance wave numbers are obtained; then the one-dimensional wave number spectra corresponding to the distance wave numbers are spliced in the distance direction, and a two-dimensional wave number spectrum of the whole aperture is obtained; two-dimensional Fourier transformation is conducted on the two-dimensional wave number spectrum of the whole aperture, and a full spatial resolution image under the polar coordinate system is obtained.