LiDAR plays an important role in the remote sensing of environmental elements due to its active emission, high detection accuracy, good real-time performance, and high spatial and temporal resolution. Based on the coupling relationship between the scattering spectrum and the medium environment, the direct scattering spectrum LiDAR can invert the multiple environment elements by directly measuring the energy dimension and the spectral dimension multi-feature information such as energy, frequency shift, linewidth, etc. In this paper, the recent advances in spectrum characteristics research and spectrum detection techniques of direct scattering spectrum LiDAR are briefly summarized. The detection theory and inversion models of underwater and atmospheric direct scattering spectrum are mainly introduced, as well as the existing measurement methods of direct scattering spectrum.