This research presents a new modus of electrochemical finishing as a finish process using an effective design of forming sheet electrode on zinc alloys beyond traditional process of die casting on the surface of castings instead of the conventional hand or machines polishing. In the current experiment, the author takes an outer shell of toy vehicle for instance; five types of design electrode are used and supplied with continuous direct current in the experiment of electrochemical finishing. For the design electrodes, a thin plate with small end radius and small wedge angle are associated with higher current density and provides larger discharge space and better polishing effect. The electrode with spherical head performs the best. The electrochemical finishing after die casting saves the need of hand or machines polishing just needs quite short time to make the surface of castings smoothing and bright. An effective and low-cost polishing of the surface of castings is presented.