Exhaust frame blade design method, exhaust frame blade device and aero-engine

The invention discloses an exhaust frame blade design method, an exhaust frame blade device and an aero-engine, and belongs to the technical field of aero-engines. The exhaust frame blade design method is used for designing blade profile parameters of large blades and small blades which are circumferentially arranged in an exhaust frame; the method comprises the following steps: determining an inlet airflow angle range and an incoming flow Mach value range of inlet incoming flow typical working conditions, determining the maximum thickness of a large blade according to exhaust frame structure limitation, and designing inlet structure angles of large and small blades by taking the parameters as a design basis; and then the numerical ranges of the outlet structure angle, the leading edge wedge angle, the trailing edge wedge angle, the bending angle and the mounting angle are sequentially determined so as to meet the functional requirements of the engine under the typical working condition. The engine exhaust fr