This paper presents a theory and related experiments on centrifugal barrel finishing. A calculation for the centrifugal force in the barrel is described. The limitation of the ratio between the rotation speed of the tubs and turrets, and values of polishing efficiency are determined by the calculation and compared with experimental results. It can be understood from the results why the polishing efficiency of the centrifugal barrel is far higher than that of the ordinary rotating barrel. Finally some considerations on design criteria are mentioned.