A new deposition method is described using EDM to deposit tool electrode material on workpiece in air. Then by exchanging the polarities the deposited material can be removed selectively, thus micro structure can be fabricated. First, the EDD realized conditions are predicted. Then with ordinary brass, steel and tungsten electrodes and high-speed steel workpiece, EDD experiments are carried out to obtain micro structure in air. With continuous deposition strategy of single cylinder, a HIT character type array made up of 15 micro cylinders is deposited. And micro three-dimensional spiral structure can be obtained with brass electrode using feed of only z axis. The 19-circle micro spiral structure is 0.19mm in external diameter, 0.1mm in wire diameter and 3.39mm in height. Measurements show that deposited material has obvious delaminating structure and is corrosion resistant, whose components depend on those of the tool electrode material.