Abstract: Airborne laser depth sounding(lidar bathymetry) is thought to be one of the most promising techniques for rapid and high density sounding of shallow waters.As we know,there exist two types of scanning mode for airborne laser bathymetric system(ALBS).When running the first mode,the system gains good computation efficiency but loses its stability.Contrarily,when running the second mode,the system gains its stability but loses computation efficiency.Nowadays most of ALBSs have changed their line-scanning mode to the new ellipse-scanning mode due to the great advancement in the computer technology.On the basis of the ellipse-scanning mechanism,this paper deduces a series of mathematical models for ALBS's data-processing and evaluates the models'accuracy by analog-computation.Finally this paper analyzes the characteristics of the ALBS's sea-surface scanning track.