Applying copper nanowires (CuNWs) composite transparent conductive electrode (CTCE) as transparent conductive anode, a flexible organic light-emitting device (OLED) is demonstrated in this paper. Ultralong CuNWs were synthesized by a simple hydrothermal method. The random conductive grid of CuNWs was transferred to the surface of flexible substrates by vacuum filtration method. In order to reduce the surface roughness and improve work function, polymethyl methacrylate (PMMA) solution and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solution were spin-coated on the surface of CuNW transparent conductive electrode (TCE) in turn. The CuNW/PMMA/PEDOT:PSS CTCE was applied to an OLED, and the experiment shows that the OLED was of high efficiency. On comparing the OLED with PEDOT:PSS TCE, the maximum brightness and maximum current density of the OLED with CuNW/PMMA/PEDOT:PSS CTCE were increased by 104% and 4 times, respectively.