The invention discloses a turnover-preventing positioning apparatus used for high-speed data line cabling. The turnover-preventing positioning apparatus comprises a bed body; a rotary rod is arrangedon the bed body in a run-through manner; the outer side of the rotary rod is sleeved with a conveying roller; the outer side of the conveying roller is sleeved with a conveying belt; a clamping mechanism is fixedly arranged on the outer side of the conveying belt; the clamping mechanism comprises a left clamping block and a right clamping block; the right clamping block is arranged on one side ofthe left clamping block; a connecting rod is arranged on the top of the bed body; guiding mechanisms are arranged on the top of the connecting rod; the guiding mechanisms are arranged on the two sidesof the clamping mechanism; each guiding mechanism comprises a guiding vertical rod; and a guiding cranked rod is fixedly arranged on the end part of the guiding vertical rod. By virtue of setting theclamping mechanism and the guiding mechanisms, the cable can be clamped and fixed effectively while the cable can be conveyed, so that a cable turnover phenomenon in the conveying process can be avoided effectively, thereby avoiding influence to the finished product performance caused by cable turnover, and effectively improving the quality of the finished product.