LiDAR can obtain the three-dimensional space coordinates of the target, while receiving the echo radiation intensity reflected from the target, which can achieve the integrated acquisition of geometric characteristics and spectral information for targets. However, due to the influence of various factors, such as distance, incident angle, and atmospheric attenuation, the quality of the original intensity signal cannot meet the requirement of subsequent applications, then affecting the promotion of space and spectrum integration application. In this paper, starting from the generation of LiDAR intensity, its principles, characteristics, and applications are discussed. Then, the research status of intensity correction at home and abroad is reviewed, concluded, and summarized. Finally, the possible future research directions are prospected. With the increasing demand for integrated acquisition of spatial-spectral data by remote sensing technology in the future, the advantages of spatial-spectral integration of LiDAR technology will be greatly improved and widely used.