A new micro EDM method is described. First, the basic principles of micro EDD are analyzed and realized conditions are predicted. Then with an ordinary EDM shaping machine and electrode brass, steel and tungsten, a large number of experiments are carried out in air to obtain the effects of different processing parameters on micro EDD. A micro cylinder with 0.19mm in diameter and 7.35mm in height is formed on high-speed steel surface. By exchanging the polarities of electrode and workpiece the deposited material can be removed selectively, thus the reversible machining is realized. In the end, measurements show that the deposited material is compact and hardened, whose components depend on the tool electrode material although Zn in brass electrode is oxidized to ZnO.