The CuWCr composites were respectively fabricated by the mixture of W and Cr and WCr alloyed powders, followed by sintering and infiltration. Vacuum arcs on CuWCr composites were observed by a digital high-speed video camera. The morphologies of the composites before and after arc erosion were characterized by a scanning electron microscope. The results show that the microstructure CuWCr composites prepared by WCr alloyed powders becomes finer and more uniform, and, thus, has good characteristics of diffusive arcs and arc erosion resistance. In addition, the composite prepared by WCr alloyed powders has excellent electrical properties such as high breakdown voltage, low chopping current and long arc life. Arc erosion zones of the CuWCr composite fabricated by WCr alloyed powders become more dispersive and uniform on the surfaces with some shallow erosion pits. During the course of arc evolution, the dispersed arcs are caused by the split of electrical arc.