The invention relates to a tire case drum right angle shrinkage device for an aircraft radial tire building machine. The tire case drum right angle shrinkage device comprises a left ring body and a right ring body which are connected through ring body connecting rods. The radial surface of the left ring body and the radial surface of the right ring body are each provided with a plurality of side pressing blocks distributed circumferentially. The circumference of the side pressing blocks are concentric with the corresponding ring body. The side pressing blocks can conduct synchronous radial expansion on the corresponding left ring body and the corresponding right ring body so that the diameters of the circumferences formed by the side pressing blocks are changeable. The tire case drum rightangle shrinkage device is used for pressing tire case cord fabrics to the right-angle end of a tire case drum after all the side pressing blocks on the two ring bodies conduct synchronous shrinkage when the tire case drum is attached to the tire case cord fabrics. When the tire case drum expands in the radial direction, the tire case cord fabrics is wrapped outside the right-angle end of the tirecase drum in a right-angle mode.