To provide a method for operating capable of simply regulating an ink roller speed X or a key opening δ by removing defects of complicated and slow starting of an operation and a wrong productivity due to many times complicated regulations of the speed X and the key opening δ at each time when a design areal ratio is changed and operated.

The method for operating offset rotary press comprises the steps of calculating an ink amount from a design area, deciding the ink roller speed X from key opening at each blade by predetermined key opening conversion function and an ink roller speed conversion function, then deciding the opening amount δ between each ink roller and the blade according to δ=d×f(X), wherein X is the ink roller speed by setting an opening correction coefficient Y=a/X=f(X) between the ink roller and the blade, previously digitizing the value of the Y to the X in a range that Y=a/X=f(X) is not satisfied, and calculating the δ.