Abstract: Molecular dynamics simulations were conducted to investigate the high-speed grinding process of monocrystalline silicon with a single diamond abrasive grain. By analyzing the morphological characteristics of chips, phase transformation and dislocation movement in subsurface, the influence of grinding speed on subsurface damage and integrity of ground surface were investigated combining the evolution of superficial area in workpiece. The simulation results show that the bump of material in the front of the abrasive grain increased at a higher grinding speed. When the grinding speed was more than 200 m/s, the increment of volume of the chip was not obvious. However, the average temperatures at the contact area increased substantially due to the squeezing and friction generated between the grain and workpiece. The interactions among the grinding temperature, grinding force and adhesion effect gave diversity for friction coefficient in a rule of " high to small”. As a result of the lattice deformation, lattice reconstruction and amorphous phase transformation, the grinding force presented a critical fluctuation in the chip formation. For machining the silicon, a kind of brittle material, the damage layer in subsurface experienced a change of " thin to thick” with the grinding speed going up. When the grinding speed increased, the atom lattices beneath the grain had no enough time for the rearrangement, which resulted in less amorphous structure as well as a consequence of a thinner damage depth. While the grinding speed was over than 150 m/s, the dominant factor was the high temperature in the machining area, a thicker damage layer was induced on account of the dislocation nucleation and motion.