The element distribution in electrode surface, the microstructure and morphology of the W-15wt%Cu electric material were studied under DC condition. The transformation and erosion mechanism of the material in the DC arc was discussed. The results show that the DC arc causes the melting of the surface in anode, the transferring of copper ion and depositing on the cathode surface. The deposition of copper in cathode surface reduces the contact resistance. The decomposition of metal oxide is helpful to extinguish arc by absorbing the arc energy. Meanwhile the particles of W suspend in the melt pool which will increase the viscosity of the melt Cu and help to reduce the splash of melt drop and arc erosion. The W-15wt% Cu contact material shows better performance under DC condition compared to the other materials