Abstract: Dual-comb spectrometers possess the advantages of both high resolution and short measurement times, which make them powerful tools in studying molecular spectroscopy.This article explores the principles of dual-comb spectroscopy and makes a comparison with traditional Fourier transform spectrometers. We then explain in detail both the structures and the molecular absorption results of several typical dual-comb spectrometers. With the development of optical frequency combs and detector techniques in the mid-infrared region, dual-comb spectroscopy is bound to be widely used in such fields as air pollution and breath gas detection in the near future.