Significance  Bathymetry is one of the fundamental tasks in oceanography, holding great value for marine surveying and mapping, hydrodynamics, marine biology, and related research. As an emerging bathymetric method, LiDAR offers advantages such as high measurement accuracy and efficiency. It also enables seamless integration of terrestrial and submarine topographic mapping. However, current LiDAR applications still face challenges such as turbid water scattering, attenuation, and high costs, which constrain further technological development. Therefore, a review of the evolution of linear-system bathymetric LiDAR is of great significance for future technological breakthroughs and expanded applications.

Progress  In terms of technical principles, the bathymetric mechanism of linear-system LiDAR is introduced, covering processes such as laser emission, propagation in medium, laser echo, and signal processing. The fundamental principle of LiDAR bathymetry is based on the time-of-flight of photons to calculate distance. Since the blue-green band represents the optical window of water, most existing LiDAR systems use laser sources within this band to maximize detection depth. The development of LiDAR has gone through several stages: 1) Early exploration, involving theoretical model establishment and verification of technical feasibility in clear shallow waters; 2) Technological advancement, with performance improvements and key technological breakthroughs; 3) Maturity, marked by commercialized products and expansion of application fields. Key technologies discussed include: 1) High-power narrow-pulse laser emission technology; 2) High-precision echo signal reception technology; 3) Signal processing techniques for complex environments. Finally, the current challenges facing linear-system LiDAR are analyzed, mainly including limitations in detection accuracy and depth, disturbance from complex marine environments, and issues related to system cost and portability, along with potential targeted solutions.

Conclusions and Prospects  Bathymetric LiDAR technology has become an essential foundation in the field of marine surveying. As human exploration of the ocean continues to deepen, LiDAR will further expand its applications and play an increasingly indispensable role. This study aims to outline the developmental trajectory of bathymetric LiDAR technology, introduce key milestones in its progress, and point out existing issues—such as detection performance, anti-disturbance capability, signal processing algorithms, and hardware portability—along with potential solutions. It is expected to provide a reference for future key technological breakthroughs and performance enhancements.