A modified coating layer had been deposited on the surface of the workpiece with the electrode made of special materials by normal Electrical Discharge Machining (EDM) method in the recent years, and the surface performance had been improved. But, it also has been found that the deposited materials from the electrode can’t be melted fully on the workpiece and the compact coating can’t be formed because of the quencher and quickly heated effect with normal EDM pulse generator in the experiments. And there are other problems existing such as residual stress, crack and so on. In order to solve the above problems, a kind of special Electrical Discharge Coating (EDC) pulse generator is designed in this paper. The hard coating with less crack and higher coating efficiency can be expected with this special generator.