Frequency-modulated continuous-wave (FMCW) synthetic aperture radar (SAR) is a newly proposed imaging radar system, which combines FMCW technique with synthetic aperture imaging technique. FMCW SAR has the advantages such as small cubage, light weight, cost effective, low power, high-resolution, low probability of intercept etc. In this paper, several application backgrounds of FMCW SAR and its primary parameters are concluded. Finally, the further development trend of FMCW SAR based on its development progress is discussed.