Electrochemical polishing is a well-known method in finishing of complex shapes with high surface quality. Inner surface polishing of complex parts with high precision can also be easily done by this method. In this research, barrel chamber’s surface, with numerous serial surface angles, is analyzed so that, according to the various set ups, the optimized polishing parameters are obtained. The comparison between electrochemical polishing and conventional methods from this point of view, shows good advantages of this method, so that, the machining time is more than thirty times less and produces very high surface quality. Besides, the dimensional accuracy of the workpiece repeatability process in this polishing method is noticeable.