<p>The dynamic characteristics of the feed system in multi-axis CNC machine tools have a significant impact on the machining quality of workpieces. Establishing a performance evaluation system for the dynamic characteristics of the feed system can help improve the machining quality of parts. First, the feed system of a double-swing five-axis machine tool was used as the research object. Based on the lumped parameter method, dynamic models of the translational axis and rotational axis feed systems of the double-swing five-axis machine tool were established, resulting in the transfer function between the motor output angle and the translational axis output displacement. Next, a modal parameter identification method based on the particle swarm optimization algorithm was proposed. By analyzing the vibration response signals collected from static tapping and idle running excitation of the machine tool, the modal parameters were identified, and the effects of stiffness and damping variations on the feed system were studied. Finally, taking a specific machine tool as an example and considering its actual operating conditions, the dynamic characteristics of the feed system were evaluated using the intuitionistic fuzzy analytic hierarchy process (IFAHP). The evaluation was based on inherent frequency and average amplitude as key indicators.</p>