Co/Cu/Fe nano-sized sandwich thin films have been prepared by electron beam evaporation. 5 μm×5 μm Co/Cu/Fe sandwich heterojunction was made using photolithography and lift-off process. The bipolar output signal of Co/Cu/Fe junctions has been measured and analyzed. The effects of applied magnetic field angle (referring to the normal of the junction plane) and injecting spin-polarized current on the output signals have been studied, and the measured results were discussed.