In order to reveal the impact of both process parameters and blank size on the length of the roll forging of coupler yoke，the maximum torque of roller and the filling rate of coupler yoke forgings，a mathematical model is constructed by taking a 13B coupler yoke as the research objective and on the basis of the model-based calibration ( MBC) in the software Matlab． In this model，the length of blank is set as local variable，roller clearance，friction coefficient，blank temperature and roller speed are set as global variables，and length of roll forgings，maximum torque of roller and filling rate of coupler yoke forgings are set as the objective function． Then，finite element simulation is conducted，and objective function is optimized through the CAGE toolbox in the MBC． Thus，both optimized look-up table and optimal parameter combination of forging forming are obtained，in which the blank size is 160 mm × 865 mm with a roller clearance of 3 mm，a friction coefficient of 0. 67，a blank temperature of 1 180 ℃ and a roller speed of 15 r/min． Finally，the proposed method is proved to be feasible through the contrast of finite element simulation results and actual production． Therefore，this study offers an effective technology to control the length of precision roll forgings and the filling rate of coupler yoke forgings