Transient image is a fast image sequence in which a scene responds to light pulses. By capturing the time dimension information， the transient image realizes the use of the scene information contained in the time domain， and the non-line-of-sight imaging is the most typical application of transient images in the field of scene analysis. It is a technology for imaging objects or scenes outside the line of sight， and has emerged at home and abroad in recent years. According to different imaging mechanisms， this paper classifies different imaging methods of transient images， and compares a variety of non-line-of-sight imaging algorithms based on transient images according to different algorithm principles or implementation effects. Finally， the challenges of non-line-of-sight imaging technology based on transient images are summarized， and the future development direction is prospected.