Abstract: By the use of Hamilton's principle,a set of aeroelastic equations is formulated to describe the motion of an arbitrary mistuned rotating cascade with high aspect ratio,flexible pretwisted,nonuniformed blades.A two dimensional aerodynamic theory is used to calculate unsteady force and moment coefficients for vibrating aerofoil in supersonic unstalled cascade.This set of equations is of great value to a fan blade with the inertial,structural and aerodynamic coupling in bending bending torsion.Results obtained from the aeroelastic stability analysis of a real fan stage show that amplitude and different order of mistuning and other kinds of structural properties have an apparent effect on boundaries of supersonic unstalled flutter.