Cut the potato and the green pepper into thin strips. Cut the garlic into slices. Immerse the potato strips in cool water to remove excessive starch. Drain. Heat the oil in a flying pan and sauté the Chinese prickly ash to make an aroma. Remove the Chinese prickly ash and add the garlic to make its aroma as well. Add the potato strips and vinegar and sauté. Add the salt and sugar and sauté until the flavoring sauce turns thick and wraps the materials. Add the green pepper and mix it up with other materials.