Abstract: Briefed in the paper are the two pass adjustment methods respectively for the two currently most representative three-roll MPMs.With relevant boundary conditions simplified,and the Φ168 mm PQF and the Φ159 mm FQM taken as the study objects,analysis is conducted on displacements of the key pass points and shifting statuses of the pass centers of the mills after swing screwdown and radial screwdown,when rolling pipes with typical sizes.Also analyzed are the extent of influences by the said two different pass adjustment types on the pass accuracy as well as the pipe wall thickness accuracy.