A new method called compression and setting round was proposed to replace the mechanical expanding to reduce the ellipticity and increase the compressive strength of large pipes. The compression and setting round by mold was completed by a upper die and a lower die whose cavities could be closed to a whole round. In order to reduce the springback, the within and outside walls of the pipe must be compressed into the plastic deformation, namely, the compression rate must be sufficient. In this paper, the small curvature plane bending theory of curved beam was used to analyze the compression and setting round of the pipe. The springback equation of the compression and setting round was deduced to express the relationship between the curvature radius of any poin on cross-section center line after springback and the initial geometric parameters, material properties and the compression rate of the pipe. After a compression experiment,the ellipticity is less than 0.12%,which fully meets the technical requirements of line pipes for 0.5% to 1% in practice. Furthermore,the relative ellipticity deviation of theoretical analysis and experimental results is less than 0.09% and the relative geometric size deviation is less than 0.19%. Experimental results verify that the springback equation of compression and the setting round method have important application values.