To make a further understanding of the materials removal mechanisms of polycrystalline sintered silicon carbide (SiC) ceramics, a single diamond grain scratch platform was built to carry a single diamond grain scratch test on the polycrystalline solid phase sintered silicon carbide ceramics. In the scratching process, the chip formations were observed and the scratching force signals were collected and analyzed, then the scratch morphologies were observed with an optical microscope.The results show that the chip forms of sintered SiC ceramics are classified into continuous chips and collapsing chips,and scratching process has in turn experienced continuous chips formation stage, continuous chips accumulation stage and chips collapsing stage. Besides, when the scratching speed v=0.01mm/s, there is a significant turning point of tangential and normal scratch force at the time of 16s. Whereas, at the scratching speed of 0.04mm/s, the turning point just appears in normal scratching force, and the normal grinding force fluctuates heavily when the scratching time exceeds 12.5s, which may be due to the collapsing chips formation. What’s more, even the SiC ceramic materials are removed in ductile mode, there are fishscales cracks appearing on the scratching surface. When polycrystalline SiC ceramics removed in brittle mode, the fractured surfaces transforms from the discontinuous region into the continuous region with the increasing scratching depth. Eventually,the fractured surface extends to the non-scratching area.