High efficiency milling experiment on natural marble were carried out using TiCN/Al2O3 coated ball end mill tools.The wear mechanism of tool was discussed by analyzing the wear morphology of coated tools and the elementary composition of wear surface with scanning electron (SEM) and energy spectrum detection (EDS).The results show that the wear of coated tools includes adhesion wear,abrasive wear,fatigue wear and fretting wear.The sticking substance and scratch appears on the flank surface of cutting tool at the beginning of the cutting process and the flank surface material is desquamated by the effect of intermittent cuttingimpact.The vibration of cutting system is enhanced under low cutting speed,the fatigue cracks is extended in the substrates of cutting tools,which decreases the surface strength and is easy to cause large area gouging abrasive wear.The comprehensive function of fretting wear intensifies the wear of coated tools and damages the cutting performance of coated tools.