Abstract When the workpiece is sliced by using wire electrical discharge machining (WEDM), owing to the material removal mechanism of melting and evaporation, numerous overlapping discharge craters and recast layer can be generated on the workpiece surface, leading to the high surface roughness. In this study, a method called WEDCM, which uses wire electrochemical machining (WECM) to remove the recast layer and reduce the WEDM surface roughness, is proposed. An analytical model is developed to identify the appropriate feed rate of the wire electrode during the stage of electrochemical dissolution. The calculation results show that in order to dissolve the recast layer, the wire feed rate should be reduced with the increase of the movement distance. The experiments are carried out on the same machine tool with the same electrolyte (deionized water) to verify the model. The experimental results show that the recast layer on the WEDM surface can be dissolved and the surface roughness can be reduced with WEDCM. Two factors which have great influence on the final surface roughness are also discussed.