Abstract: Described in the paper is an analytical calculation method for the three-roller steadier for CTP.The formulas for the separate rotation angles of the drive rocker and the driven rocker of the dual-rocker mechanism are solved via the triangle analysis method,and thus the calculation formula for the geometric center coordinate values of the acting circles of the three centering rollers are analyzed,and the deduced formula is used for calculation-verification of the three centering rollers.The said calculation method shall facilitate the design development and verification of the centering device.