In order to determine the high-speed Computer Numerical Control (CNC) lathe linear servo system control parameters reasonably, the linear motor feed system control model was established based on analysis of high-speed linear feed system control principle, and the linear motor feed system transfer function was established, and servo dynamic stiffness factors were analyzed. The control parameters of the servo system and actuating mechanism parameters of feed system on the effect of the linear motor servo dynamic stiffness were analyzed using MATLAB software. The simulation results show that the position loop proportional gain, speed loop proportional gain and speed loop integral response time are the biggest Influence factors on servo dynamic stiffness. The displacement response is reduced under the cutting interference force step inputting, while the position loop proportional gain, speed loop proportional gain and speed loop integral response time are increased, and the servo dynamic stiffness is increased, the number of system oscillation is also reduced, and the system tends to be stable.