The structural dynamic equations for blades were introduced in this paper.Through numerical solving the aerodynamics-structure coupled equations

a 2-D unsteady viscous flow in cascade was investigated under gas-solid coupled conditions

and a preliminary analysis of the cascade flutter was prosecuted.The flows of different reduced frequencies were computed for two blade profiles respectively.By comparing the relative parameters changing with time in the oscillating cascades under different conditions

it indicates that the reduced frequency is an important factor in determining whether the blade flutter onsets or not.