For the spindle speed of high precision CNC milling machine up to 160 000 r/min,the cutting torque of blades less that 0.005 N·m,an aerodynamic calculation and graphic design have been done for the swinging angle milling head spindle-driven turbine-type air motor cascade,and numerical simulation of aerodynamic character has been conducted by using software Fluent.The results have been compared with the theoretical calculations to verify the correctness of simulation.The change of aerodynamic characterictics with inlet angle,leaf number and blade height,has been studied and the best parameters are inlet angle 21°,leaf number 36,and blade height 3.5 mm.