Abstract: In view of the phenomenon that the blade is coupled by rotating softening effect and dynamic stiffening effect,which leads to the change of its modal characteristics under the operating state of large-scale blade,a vibration analysis method of rotating blade based on perturbation modal analysis is proposed. In this paper,two blade models of 0.89 m and 61.5 m are established. Through numerical simulation,the influence of two effects on blade frequency at 0-50 r/min speed is analyzed. Based on the variation rule of calculated frequency difference Δf,the correlation between the three main modes of blade and the two effects is studied. Finally,in order to verify the accuracy of numerical simulation,experimental modal analysis and numerical simulation results are compared by hammering method. The experimental results show that the errors of first and second order mode frequencies are within 1%,and the calculation results in this paper are more accurate.