In abrasive machining for brittle materials such as monocrystalline silicon and optical glass， the key to obtaining a high-quality machined surface is that the single abrasive grit's actual scratching depth should be less than the critical cutting depth of ductile-to-brittle. However， when calculating the actual scratching depth of the single abrasive grit， the influence of indentation contact elastic deformation between monocrystalline silicon and abrasive grit must be considered. Owing to the structural similarity between the diamond abrasive cutting edge and the tip of the Berkovich indenter， the indentation contact deformation between monocrystalline silicon and the Berkovich indenter is theoretically analyzed and experimentally investigated in this study. Based on the nano-indentation experiment principle， the calculation equations of indenter displacement depth of Berkovich indenter loading press into monocrystalline silicon and indentation depth on monocrystalline silicon after unloading are established. A simplified calculation equation of contact elastic deformation between the Berkovich indenter and the monocrystalline silicon specimen is established by transforming the contact between them into the contact between sphere and plane. Nano-indentation experiments are carried out on the monocrystalline silicon. The measured nano-hardness of monocrystalline silicon is 12.22 GPa， and the effective elastic modulus is 173.09 GPa. The experiments were used to obtain the elastic contact stiffness， indenter displacement depth， and indentation depth of the nano-indentation contact between the monocrystalline silicon and the Berkovich indenter. The contact elastic deformation exceeds 50% of the indenter displacement depth. This study's findings are helpful for optimizing the process parameters for diamond wire saw precision slicing and the precision grinding of monocrystalline silicon.