The cylindrical air film cantilever flexible support structure model was established based on the three-dimensional SolidWorks software,and the influence of the flexible support structure on the stability of the cylindrical air film seal structure was analyzed.By using a one-way fluid-solid coupling simulation method,the influence of the thickness of cantilever support plate,the material of cantilever flexible support structure,the number of cantilever supports,and the gas film operating parameters of rotational speed and differential pressure on the maximum deformation,maximum stress and strain of cantilever flexible support structure and floating ring were studied.The results show that as the thickness of the cantilever support plate increases,the average deformation and the average equivalent stress decrease.With the increase of the number of cantilever support plates,the maximum deformation gradually decreases,and the maximum equivalent stress first increases and then decreases.Among the four cantilever support plates of aluminum alloy,beryllium bronze,stainless steel and titanium alloy,the maximum deformation of stainless steel cantilever support plate is the smallest and the maximum equivalent stress is the largest.cylindrical gas film seal structure.With the increase of rotational speed and pressure difference,the maximum deformation and the maximum equivalent stress of the cantilever support plate increase gradually.Within the scope of research,the flexible support structure can reduce the deformation of the floating ring,and the deformation of the floating ring is less than the minimum gas film thickness,which ensures the stable operation of the sealing structure.