The form of the up and down abnormities part is very special，processing this kind of part can't use the routine method .WEDM can process the up and down abnormities part. In order to obtain the ideal processing result , when the NC processing program is compiled , should act according to special details of the part, correctly determine corresponding points position and quantity of up and down surface, correctly input H1 H2 and HCD these three parameters, correctly assigns XY surface and UV surface. Because the guide pulley motion way of DK7725e moves for the single guide pulley, so it only can process small taper up and down abnormities part. Have analyzed the common failed reason, and put forward the countermeasure.