Numerical-control aligning device and method for cover flanges of large-size rotary body

The invention discloses a numerical-control aligning device and method for cover flanges of a large-size rotary body, and belongs to the field of mechanical manufacturing. The numerical-control aligning device comprises the large-size rotary body placed on a numerical control bracket, and numerical-control flange installation devices located at the two ends of the large-size rotary body. The center lines of transverse moving rails of the numerical-control flange installation devices coincide with the center line of the large-size rotary body, longitudinal moving rails can move on the transverse moving rails in a numerical control mode, and flange supporting platforms are used for being connected with and fixing the cover flanges and can move on the longitudinal moving rails in a numerical control mode. The method comprises the steps that, firstly, installation discs are aligned to and installed on the flange supporting platforms, and the cover flanges are aligned to and installed on the installation discs; se