Abstract: The wire cutting experiments of Cr12MoV die steel were carried out in different media. The author uses the scanning electron microscope to observe the micro appearance of the workpieces and the electrode wire etching surface, analyzes the effect of the machined surface quality and the wire electrode wear by working medium and puts forward that the double medium supply mode of gas and liquid can improve the surface quality and can decrease the wire loss. The result shows that the fishing surface quality in gas-liquid dual media is much better than that in liquid, slightly better than that in gas, but also the loss of electrode wire is close to that in liquid and less than that in gas.