Abstract: This paper presents an investigation of blade excitation during rotating stall in a single stage axial flow compressor with various geometrical parameters,such as blade stagger and cascade solidity at the mean radius varying from 32.9 to 47.9 and from 0.583 to 1.165,respectively,and the axial distance between rotor and stator from bto 5.7b.The blade vibration was measured with strain gages on the blade.During rotating stall as the cause of blade excitation,the flow field was simultaneously deter mined by fast response dynamic pressure transducers.The rotational speed of the compressor varied from 8130 to 12500 rpm.The charact eristics of unst eady flow during rotating stall were studied in detail. The prediction criterion of the blade excitation frequency during rotating stall has been set up.The agreement between theoretical and experimental results indicates that the criterion is feasible.