We demonstrate a novel ultraviolet (UV) light irradiation strategy to rapidly weld Cu nanowires (NWs) network and remove the organic residues for transparent electrodes. Shortly irradiated by UV light source, the Cu NWs could achieve junction welding in the absence of any thermal annealing process. This Cu NWs network shows high optoelectronic performance (39 Ω/sq at 90% transmittance at 550 nm) and outstanding flexibility under bending and twisting. Completely transparent light-emitting diode (LED) chips array was fabricated and has been lighted with bright top-surface emission. This method could provide a fast and convenient way to fabricate Cu NWs transparent electrodes onto various optoelectronic products.