An investigation of some problems such as chip formation and surface generation in nanometric cutting mechanism based on molecular dynamics(MD) simulation is presented.It shows that chip formation is similar to that observed in macro-scale cutting.The movement of some micro-dislocation is the main cause of formation of chip and surface.Surface generation is notably affected by very small cutting force vibration.The highest stress appears in tool cutting edge,and it may cause wear,so it is necessary to build a MD model of tool wear.