A model and harmonic simulation analysis and experiments have been done separately by the finite element analysis software ANSYS and its first five natural frequencies,vibration models and the frequency response curve of rotating mirror were obtained.In the displacement frequency response curve of rotating mirror,the resonance bands of torsional vibration and bending vibration were overlapped,and the maximum peak value at the first bending vibration was greater than others.The stress of the first bending vibration was much larger than the others and the maximum stress appeared in the shaft.The main form of failure is the damage of the shaft,and the front bending vibration is the main reason of rotating mirror failure.With the model of rotating mirror natural frequency sensitivity compiled by ANSYS Parametric Design Language ,the numerical analysis and experiment of rotating mirror natural frequency have been done using the Probabilistic Design System of ANSYS to study the interrelationship between physical dimensions and the natural frequencies.The numerical results reveal that the dependency of the circumcircle radius R5 of mirror body and the radius of shaft 2 with the same frequency is opposite,and the degree of correlation of R5 and R2 is higher than anther.The results of experiment show that the change mode and degree due to the same change of different structural parameters of rotating mirror is identical with numerical analysis.This study provides a quantifiable indicator for dynamic design of rotating mirror.