The main object of the present work was to develop an ultrasonic aided electrical discharge grinding (UAEDG) methodology to remove the re-solidified layer through the grinding induced by a metal matrix composite electrode prior to the re-solidification of molten material. A metal matrix composite (Cu/SiCp) electrode, with an electroless pretreatment of Cu coating on SiCp to enhance bonding status between Cu and SiCp, was employed to study the UAEDG technology. The machinability of the mold steel SKD11 was investigated by the combined technologies of UAEDG. The machined surfaces of these materials were examined by optical microscopy(OM)and their surface roughness measured by a profilemeter.