The invention discloses mounting assisting equipment of air chamber prepressing, and is used for performing press fitting on an upper film cover and a lower film cover of an actuating mechanism. The mounting assisting equipment comprises a mechanical mechanism, an air path mechanism and a circuit mechanism, wherein the air path mechanism comprises an air cylinder and an air path unit, and the air path unit is used for driving the air cylinder to move, then the upper film cover is driven by the air cylinder to be in press fitting with the lower film cover; the mechanical mechanism comprises a footstock structure, a middle structure and a base structure, wherein the middle structure is arranged at the top of the base structure, the footstock structure is arranged at the top of the middle structure, the lower film cover is fixed to the base structure, an air cylinder structure is fixed to the footstock structure; the movement of the air cylinder is controlled by the circuit mechanism through an air pipe mechanism. The mounting assisting equipment, disclosed by the invention, can be used for the mounting assisting of multiple actuating mechanisms, a mounted product is stable in quality, high in efficiency, safe to use, and simple to operate, most accessories can be directly bought in the market, the maintenance is convenient, and the mounting assisting equipment is convenient to generalize and apply.