The simulation model of single crystal aluminum is established based on the theory of molecular dynamics. This paper makes a comparative study of effects on the nanocutting process between tool ware and unworn. The research shows that, in the case of tool wear, the machined surface quality has been reduced, and a large number of dislocation and other defects have appeared on the substrate. At the same time, cutting forces also all increased, and the tool edge radius wear has the most significant influence on the cutting force. Under the same cutting conditions, the cutting force is increased by approximately 17.78%, and the effect of tool flank wear and tool rake face wear on cutting force is basically same, which is increased by about 7.98%. Tool temperature and workpiece temperature have varying degrees of increase, and the workpiece temperature rise higher. The tool edge radius wear has the greatest influence on the temperature rise, when the stable cutting is achieved, the average temperature of the tool is increased by about 7.2% compared with the unworn tool.