Abstract: Carbon fiber-reinforced polymer composites (CFRP) exhibit strong heterogeneity and anisotropy, consisting of brittle fibers and tough resin at the mesoscopic scale. The contradictory machinability between these two components easily leads to severe mechanical-thermal damage during grinding, resulting in processing defects such as fiber pull-out and resin smearing, which degrade the service life of CFRP components. Focusing on the mesoscopic material mechanism, this study took CF/PEEK, a typical carbon fiber-reinforced plastic material, as the research object. A three-dimensional mesoscopic finite element simulation model for single-grit scratching was established to elaborate the mesoscopic material removal process and damage mechanism of CF/PEEK under two typical fiber angles (0° and 90°) during single-grit scratching. Additionally, a single-grit scratching experimental platform was built to conduct experiments with multiple scratching parameters, revealing the influence of different parameters on the scratched force and surface morphology. This research provides a theoretical basis for the high-quality grinding of CFRP materials.