This paper studies the performance assessment of magnetic-assistance electrochemical finishing using an effective design system and magnetic force to the electrolyte to assist the dregs discharge on zinc alloy beyond die casting by electrochemical finishing as a finish process on the freeform surface of castings. An outer shell of toy vehicle is taken for instance in the experiment. A small distance between the two magnets or large magnetic field intensity provides larger magnetic force and discharge ability. A higher current rating with magnetic-assistance can avoid the difficulty of dreg discharge, thus reducing the finish time. Pulsed direct current can slightly promote the finishing effect, but the machining time is increased. Thus the magnetic-assistance electrochemical finishing without pulsed current is recommended for the finish process. It is a great contribution that the magnetic-assistance electrochemical finishing just needs quite short to make the freeform surface of workpiece smooth and bright.