The invention provides a CuO/Ni core-shell nanowire and a preparation method thereof. According to the preparation method, an AOO (anodic aluminum oxide) template is taken as a cathode, a carbon rod is taken as an anode, copper nanowire arrays are deposited in the AOO template with an electrochemical deposition method and then soaked in a phosphoric acid solution for pore expansion, thermal treatment is also performed, nickel nanowire arrays are deposited on the treated template, the AOO template containing the nickel nanowire arrays and the CuO nanowire arrays is obtained, finally, the AOO template is soaked in a sodium hydroxide solution, an aluminum oxide template is removed, and the CuO/Ni core-shell nanowire is obtained after ethanol cleaning and infrared drying. The preparation method adopts a simple process and can realize mass production, the cost is low, and the prepared CuO/Ni core-shell nanowire can be 25 mu m long.