Thin-wall components were widely used in aerospace products. However, due to the special shape of the structure and the poor machinability, traditional technologies were hard to mill the thin-wall components, milling vibration influenced in the machining process. In this paper, analytical and experimental identifications of the chatter frequencies in milling processes were presented. In the case of milling, there are several frequency sets arising from the vibration signals, as opposed to the single well-defined chatter frequency of the unstable turning process. Frequency diagrams are constructed analytically and attached to the stability charts of mechanical models of high-speed milling. We proposed the corresponding technological measures to prevent deformation.