Satellite laser altimetry technology enables the acquisition of accurate three-dimensional coordinates of ground targets， serving as a high-precision method for Earth observation. Laser altimetry data have been widely applied in areas such as terrain mapping， polar region monitoring， and forestry surveys. The terrain profile matching over natural surfaces aligns the measured terrain profiles from laser altimeters with reference terrain data to determine the positioning errors of laser altimetry measurements. This approach is currently one of the most commonly used methods for the on-orbit geometric calibration and accuracy validation of laser altimeters. However， the performance of terrain matching is influenced by various factors， including surface relief， along-track length of laser altimetry data， and the spacing of laser footprints. Related research is still in its early stages. This paper focuses on two key factors affecting terrain matching： the along-track length of the laser data and the spacing of laser footprints. Using the ICESat-2 satellite， which provides the highest observation density among current missions， we extracted and downsampled its measurement data to construct a series of laser altimetry datasets. Extensive experiments were conducted over regions in North America. Based on statistical analysis of the experimental results， this study quantifies the relationship between terrain matching uncertainty， laser data track length， and footprint spacing.