Landscape grading is mostly taught in an independent course of landscape grading, but poorly integrated with the teaching of landscape space design, because the 3D topography of the site is expressed by 2D topographic maps. Applying high fidelity DTM, based on a comparatively flat site, the author explores teaching landscape design by integrating grading in a 3-phase experiments: 1) a step-by-step training on site grading based on Civil 3D, 2) the digital surveying and terrain modelling of the design site, 3) the interaction between spatial conceptualization and grading studies. The results indicate that the students can perceive, operate and conceive the landform as a 3D space throughout the entire process from site surveying to spatial design, and grading studies is well integrated with landscape design.