Synthetic aperture radar (SAR) non-constantly accelerating target detection and imaging is a newly exploited technique. Based on the review of conventional SAR/GMTI (ground moving target indication), we introduce the SAR/MMTI (micro-motion target indication) concept which incorporates micro-motion techniques into SAR. Targets with non-constant radial acceleration are collectively referred to as MMTI targets. The comparison of MMTI, Doppler beam sharpening (DBS), SAR and GMTI indicates that the SAR/MMTI technique features cubic and higher-order phase terms in which phase periodicity may be contained. In what follows, the state of the art in the technique is in detail discussed. Further more, the MMTI related research aspects and methods to be used are recommended. Potential applications of the technique are enumerated in the end. (4 pages)