The invention discloses an automatic positioning-detecting system based on a tube-boring perforating lathe, and relates to the technical field of tube-boring automatic production lathes, and aims to solve the problem of offset of a boring tube to be machined due to inaccurate positioning. The automatic positioning-detecting system is technically characterized by comprising a rack, wherein the rackis provided with a belt wheel for conveying a boring tube; a positioning mechanism is arranged at a tail end of the belt wheel; the positioning mechanism comprises side top pieces which are arrangedsymmetrically and are positioned at the tail ends of the belt wheel; the two side top pieces are connected to one driving transmission mechanism; the driving transmission mechanism comprises connection blocks, a slide rail, a slide block, two connection rods and a cylinder; two connection blocks are arranged on outer sides of the two side top pieces respectively; the connection blocks are of L-shaped structures, the other sides of the connection blocks are fixed to the slide block; the slide block is in slide connection with the slide rail which is vertically arranged with the side top pieces;certain sides, close to the slide block, of the connection blocks are fixed to the connection rods; the other ends of the two connection rods are arranged on an output shaft of the cylinder. By adopting the automatic positioning-detecting system, the boring accuracy is increased in order to ensure machining quality.