The invention discloses a pipeline opening aligning device, and belongs to the technical field of pipeline welding. The pipeline opening aligning device comprises two correcting portions and a clearance adjusting portion; each correcting portion comprises a transverse correcting portion and a longitudinal correcting portion which are fixedly connected, and the clearance adjusting portion is fixedly connected with the transverse correcting portions in the two correcting portions and can adjust the distance between the two correcting portions; and first clamping fixing frames and movable pliersare each of a fan-shaped annular structure, and in each correcting portion, the corresponding two movable pliers and the corresponding clamping fixing frame can clamp a to-be-corrected pipeline underdriving of a first adjusting mechanism, so that the distance between the two to-be-corrected pipelines is adjusted through the clearance adjusting portion. According to the pipeline opening aligning device, the distance between the two correcting portions is adjusted through the clearance adjusting portion, and then the subsequent welding efficiency is effectively improved. The pipeline opening aligning device is used for correcting the pipelines.