The vibration in milling process plays a key role in machining, which will significantly affect the machining quality of workpiece. Some vibrations have negative influences on the workpiece surface, while particular vibrations are able to improve machining stability. Therefore, it is critical to distinguish the influence of different types of vibration on the machining quality. A simulation method of undeformed chip thickness considering process vibration is presented in this article, in which a finite element model is established to analyze the dynamic milling process of 7075-T651 aluminum alloy from the aspects of cutting force and temperature. A series of experiments are carried out to verify the effectiveness of the simulation model, and the results show that the proposed model is accurate in predicting milling force and temperature. Furthermore, the effect of milling vibration on machining performance is studied with the proposed method, in which the relationship between amplitude-frequency characteristics of vibration and milling force-temperature fluctuation is revealed. The results show that the proposed method can define the influence of milling vibration and provide a basis for distinguishing favorable and unfavorable vibration parameters of machining quality in milling.