Abstract: The influence of the tool inclination angle and the secondary feed rate on the deformation of monocrystalline silicon materials in elliptical vibration-assisted cutting was explored. A molecular dynamics simulation model for nanoscale cutting of monocrystalline silicon was first established, then the influence of the oblique angle and secondary feed rate on the deformation mechanisms of monocrystalline silicon was investigated based on this model. The results indicate that altering the tool oblique angle causes the side-flow atoms to deflect toward the tool's tilted side. Increasing the tool inclination angle intensifies the phase transformation in the workpiece and raises the cutting force, but it facilitates better subsurface quality compared to orthogonal cutting. During secondary cutting, although the residual side-flow atoms from the tool reduce the original surface flatness, secondary cutting effectively mitigates subsurface damage. At a feed rate of 4 nm, the workpiece undergoes more significant phase transformation while achieving improved subsurface quality and overall machining performance. This study provides theoretical insights into the plastic deformation mechanisms of monocrystalline silicon under varying tool oblique angles and feed rates in secondary cutting.