A air film seal for flexible supporting cylinder of wave foil structure was studied by using the fluidsolid coupling analysis method.The influences of air film thickness,eccentricity of floating ring and rotor,Poisson’s ratio,elastic modulus and the number of wave foil on equivalent stress and deformation of the supporting structure were investigated.The results show that the flexible supporting structure can meet the normal operation of the cylinder air film seal,and will not cause the destructive deformation of the floating ring and wave foil due to the excessive gas film stiffness,and the deformation is far less than the height of the wave foil.The equivalent stress and deformation of the flexible support are decreased with the increase of the mean film thickness,increased with the increase of eccentricity,and increased with the increase of the Poisson’s ratio of the supporting material.The increase of elastic modulus does not affect the equivalent stress of the flexible supporting structure,but reduces the deformation.With increasing the number of foil,the equivalent stress of the flexible support is decreased slightly and the deformation decreases significantly.