Carbon fiber reinforced polymers(CFRP) have the characteristics of low interlayer bonding strength and anisotropy and interlaminar damage,are easily generated during the cutting process.In order to study the interlaminar stress and interlaminar damage during the milling process of CFRP,a three-dimensional milling simulation model of composite materials was established.Equivalent homogeneous modeling was adopted in the structure.The three-dimensional Hashin initial failure criterion and damage evolution model were established by using VUMAT subroutine for the intralaminar element.The layers were connected by cohesive element to simulate the generation and expansion of interlaminar damage.The accuracy of the simulation model was verified by comparing the simulation and experimental cutting force values.The model was used to analyze the variation of cutting force,interlaminar stress and interlaminar damage with fiber orientation angle (0°,45°,90° and 135°).The results show that the machining damage during milling is mainly concentrated near the surface of the workpiece.Milling force,interlaminar stress and interlaminar damage are effected by fiber orientation angle.When the fiber orientation angle is 90°and 135°,the axial milling force is larger.The interlaminar stress and interlaminar damage increase with the increase of the fiber orientation angle.When the fiber orientation angle is 135°,the interlaminar stress is the largest,and the interlaminar damage is the most serious.