Dual?comb spectroscopy (DCS) is an advanced precision spectral measurement tool with high resolution, high frequency accuracy, rapid measurement speed, and broad bandwidth. Thus, it has been widely used in many fields such as spectral lidar, greenhouse gas monitoring, and combustion diagnosis. As new principles, new schemes and new technologies of dual?comb spectroscopy are emerging, it is necessary to sort out and summarize their current development status. In this paper, the principles and technical performance indexes of dual?comb spectroscopy are introduced, and the experimental schemes and advantages of four typical DCS measurement systems are analyzed and compared, including optical frequency reference, electro?optical modulation, single?cavity dual?comb, and optical?optical modulation. Meanwhile, the development status of dual?comb spectroscopy in the expansion of the operating band is analyzed. Finally, the development trend and application prospects of DCS systems are summarized and prospected, which can provide a reference for further improvement of dual?comb spectroscopy in full?band spectral measurements and multi?scene applications.