Simplification and encryption are performed on the point cloud data concerning high-relief (20 cm tillage) and low-relief (raking bare slope) terrain on a different scale of observation. We select three indicators (surface curvature, slope aspect and surface roughness) to evaluate the effect of simplification and encryption on micro-topography data analysis. The results show that simplification and encryption have a significant impact on the curvature of high-relief terrain, but have no significant impact on low-relief terrain. The slope aspect change is not significant after 5, 10 mm data simplification and encryption; 1 mm simplification has a regular impact on surface roughness; 5 mm encryption and simplification have a complex impact on high-relief terrain; 10 mm encryption has a complex impact on high-relief terrain roughness change but a regular impact on bare slope change.