Aiming at the fracture problem of an aero elastic squirrel cage, the finite element model of the elastic squirrel cage structure was established, and the stress response of the elastic squirrel cage structure under the conditions of whirl excitation, radial load and axial load was studied, and the fatigue fault mechanism analysis and experimental study were carried out. The results show that the root cause of cage fracture is that the alternating stress of the arc transition section at the end of the rib exceeds the fatigue limit of the material under the condition of online cutting, and results in the damage by high-amplitude vibration fatigue. Under complex loading conditions, whirl excitation dominates fatigue failure of elastic squirrel cage, while radial and axial loads are a secondary effect. The remelting layer produced by wire-cutting seriously affects the fatigue limit of cage, so it should be avoided in high-strength cage processing.