The six-dimensional(6-D) motion errors of helicopter loading platform(including three-dimensional(3-D) flight trajectory and 3-D attitude angle motion errors) have significant effects on point density and coverage area of the obtained laser point cloud from helicopter-borne LiDAR. Quantitatively comparing the influence characteristics of each of the 6-D motion errors on quality of the laser point cloud, has practical significance for eliminating the effects of these motion errors and for improving accuracy of the reconstructed 3-D imaging products. The transfer relationships between the 3-D position errors of the laser points and the 6-D motion errors were established. Through numerical simulation experiment, changes of point density and coverage area of the laser point cloud caused by the 6-D motion errors were quantitatively evaluated respectively and transversely compared. Simulation experimental results show that, the effects of the 3-D attitude angle motion errors are more significant, and also increase with increasing flight height; while the impacts of the 3-D flight trajectory motion errors are much smaller.