The fatigue life of the impeller is a key factor affecting the life of the fan. In view of the long cycle and high cost of the lowcycle fatigue test of the fan impeller, the impeller life needs to be estimated during the early design of the impeller structure. The numerical simulation of the lowcycle fatigue life of a certain type impeller is mainly carried out. Including fan flow field, impeller strength, fatigue and impeller modal analysis, the fan flow field and structure distribution cloud map under aerodynamic load, centrifugal, aerodynamic and coupled load impeller stress cloud map and impeller first six order modal cloud map are obtained. The results show that the centrifugal impeller is subjected to a centrifugal force load during highspeed rotation. The impact of the aerodynamic load on the structure of the impeller is relatively small. The stress is 21.25 MPa in the case of centrifugal aerodynamic coupling load at a working speed of 19,955 r/min, which is far less than the yield strength of the impeller structure material 2A70T6 204 MPa and the fatigue strength of 102.6 MPa. The impeller structure will not have yield failure and fatigue failure during the entire life cycle. The impeller can meet the 60,000 lowcycle cycle fatigue life. The dynamic characteristics of the impeller at different speeds are discussed on the basis of static analysis results, and the Campbell diagram of the modal characteristics of the impeller with the speed is drawn to give the resonance risk point, which lays the foundation for the subsequent comprehensive consideration of the impact of the dynamic and static characteristics on the fatigue life of the impeller.