Scratch tests were conducted on 6H-SiC single crystal wafers at different speeds and crystal orientations by a micron-/nano-sacle mechanical test system to analyze the friction coefficient, scratch depth of cut and surface three-dimensional morphology of the scratches. The results show that when the static load is 4 N or 6 N and the scratch speed is 0.2-1.6 mm/min, the scratch friction coefficient, scratch cutting depth and scratch width increase with the increases of load and scratch speed, and the plastic deformation area of SiC single crystal sheet increases and the surface becomes rougher. The friction coefficient is lower for low-speed scratching, thus reducing the wear rate of diamond head to some degree. The accumulation and pit degree of scratch materials at different crystal orientations are different. When the scratch crystal orientations are [1120] and [11201120], the friction coefficient, peak height and valley depth of scratch morphology are smaller, while the scratches along the [2-110] and [12-101210] crystal orientations are larger. The former is easier to realize plastic removal than the latter.