The utility model relates to a pipeline welding alignment device which comprises an annular plate (2), a lock pin (3), a hydraulic support (4), a base (5), a plate shaft (7) and the like, and is characterized in that the side wall of the annular plate (2) is uniformly distributed with jackscrews (1), and the inner annular ring is further uniformly processed with adjusting holes (6). The pipeline welding alignment device is simple in structure, convenient to operate and reliable to work, and is used for on-site welding construction of metal pipelines; and the pipeline welding alignment device has the function of circumferential alignment, so that the relative circumferential potential difference when the large-diameter pipeline is aligned can be removed, therefore, the on-site welding construction quality of the large-diameter pipeline can be ensured.