Fast axis servo system based on linear rolling guide rail was used to process the complex surface. The structure of the fast axis test prototype and the control algorithm of the fast axis control system were introduced. The mathematical model of the fast axis prototype was obtained according to the simplified model of the fast axis servo device. The control model of the fast axis servo system was analyzed, and the mathematical model of the fast axis servo dynamic stiffness was established. The influence law of the system control parameters on the dynamic stiffness was studied by theoretical simulation and experiment, and the performance of the fast axis servo system was tested after the servo dynamic stiffness was improved. The high precision of the fast axis servo system was verified by the fast axis cutting experiments on typical complex surface.