Coppertungsten (CuW) electrode is widely used in Electron Discharge Machining (EDM) because of its superb properties such as lower wear than copper, graphite and other electrodes. As well the good stability is in thermal process, CuW electrode is popular in the precision mould of cemented carbide. The CuW electrode with different content was chosen to experimentally study in depth the EDM characteristics so as to meet the optimal CuW composition of electrode in need of EDM. The influences of changes of content in composition of the electrode on EDM machining characteristics were obcerved. The relationship between characteristics of electrode, electric parameters and material remove rate (MRR), relative tool wear rate (TWR) were analyzed by using the principles of energy distribution and electron emission power. The results discover that the better process performance in MRR is achieved as voltage between electrodes is about 160 V with short pulse duration, and Cu75W can be used, whilst the minimum TWR is obtained of Cu25W with less content of Cu.