Cavity ring-down absorption spectroscopy is a direct absorption spectroscopy detection technology with high sensitivity, strong selectivity, and fast response speed. This technology has the smallest noise absorption coefficient of 10^-12 cm^-1·Hz^-1/2 due to continuous improvement and expansion of excitation light source, cavity structure, and modulation method etc. The working principle, technical characteristics, and typical applications of cavity ring-down absorption spectroscopy detection equipment are summarized in this study, and the effects of the excitation light source, cavity structure, and modulation methods on cavity ring-down spectroscopy detection technology are analyzed. Finally, the technology's application prospect is prospected by merging the typical applications of cavity ring-down absorption spectroscopy in different fields.