<p>The effect of fiber orientation angle on the fiber fracture mechanism has not been fully explored in 2D ultrasonic vibration-assisted milling (UVAM) of CF/PEEK. A model for ironing surface quality was established by integrating the motion trajectory of the tool tip with variations in ultrasonic amplitude and fiber orientation angle. Milling experiments were then conducted with conventional milling and 2D UVAM at variable amplitudes under the same parameters to compare surface morphology across different fiber orientation angles and to investigate the fiber fracture mechanism. Subsequently, the effects of these mechanisms and milling parameters on surface quality were analyzed in conjunction with milling force and surface roughness data, validating the accuracy of the ironing surface quality model. Tool wear analysis was performed alongside the optimal milling parameters, revealing that the best milling force, surface quality, and tool wear were observed at 90°, followed by 45°, then 0°, while the worst results were seen at 135°. By combining macroscopic and microscopic characteristics, a surface quality enhancement model was constructed to elucidate the coupling relationship between force and surface quality under the ironing effect at the microscopic level. To generalize the findings of this paper, the surface quality is predicted using the XGBoost algorithm, and the model’saccuracy is validated.</p>