The invention provides an improved auxiliary jacking mechanism for five-axis rotary machining blade profiles, which can strengthen the rigidity of large aluminum alloy blades in a process of rotary milling, greatly reduce the milling deformation of the profiles, and improve the machining quality of the blade profiles. The auxiliary jacking mechanism comprises a bottom plate and is characterized in that: both sides of the bottom plate are provided with a hinge pressing plate and a positioning block; and a spring jacking device is arranged on the bottom plate.