The invention relates to an accurate positioning and emptying pipe expanding machine. The accurate positioning and emptying pipe expanding machine comprises a machine frame, a power distribution control box, fixing devices, a pipe expanding mechanism, a material taking movable device, a positioning and emptying device and a blanking groove. The positioning and emptying device comprises positioningand conveying bases. L-shaped positioning and conveying blocks are arranged on the positioning and conveying bases, a separating device is arranged in the middle of each positioning and conveying block in a matched mode, the two positioning and conveying blocks are arranged in the opposite direction, and the separation distance between the inner walls of the positioning and conveying blocks is matched with the length of a pipe. A positioning and emptying movable base is matched with the right end of each positioning and conveying block, and the inner walls of the vertical portions of the positioning and emptying movable bases are flush with the inner walls of the positioning and conveying blocks. Positioning and emptying blocks are arranged on the positioning and emptying movable bases, apositioning and conveying stop block is arranged on the right side of the space between the two positioning and emptying blocks and is arranged on a positioning and conveying material blocking cylinder. By the adoption of the accurate positioning and emptying pipe expanding machine, the situation that pipelines which are placed on the fixing devices are located on the same portions can be ensured, accurate positioning is achieved, the precision of double-end pipe expansion is ensured, and the pipe expanding efficiency is improved.