The end surface angle of workpece is one of key factors that affect burr sizes and shapes. In this paper, the burr formation process of different end surface angle is simulated with elastic plastic nonlinear element method based on ABAQUS. The influence of end surface angle of workpiece on burr formation processes in high-speed machining 2024 Aluminum alloy is analyzed. The influence of end surface angle on burr sizes and shapes is studied based on equivalent shear strain and negative shear angle. The results have investigated the mechanisms of burr formation fundamentally, which is the basis of burr minimization.