The fiveaxis machine tool is widely used in the processing of largescale curved parts for the aerospace field. The processing characteristics for highspeed, highprecision and large material removal rate raise a high claim on processing stability. The main problem affecting the milling stability of fiveaxis machine tools is cutting flutter. Through the dynamic performance test of a swinging fiveaxis machine tool, the frequency response characteristics of the spindle system in different positions and the swing head in different attitudes were compared, and the position evolution law of limit cutting depth was obtained and analyzed, and the evolution law of the frequency response characteristics of the tool tip with position was obtained. The cutting stability leaflet map was constructed by using frequency domain method, and the position evolution law of the limit cutting depth was obtained. The results provide reference for the optimization of cutting parameters for fiveaxis machine tools.