Abstract: Considering the influence of the spindle runout,the static and dynamic deflection of the cylindrical helical end mills,a new milled surface generation model for numerical control milling process is developed,which takes the cutter flexibility into account.An efficient algorithm for physical simulation of three-dimensional surface topography is proposed,and simulation examples are given at last.The main idea of this paper is to predict the peripherally milled surface topography,so that the operators could reasonably select the cutting conditions.