Silver nanowires (Ag NWs) have promising application potential in electronic displays because of their superior flexibility and transparency. Doping Ni in Ag NWs has proven to be an effective strategy to improve its work function. However, AgNi NWs-based electrodes suffer from poor electrical conductivity under air exposure due to the low-conductivity NiO generated on its surface. Here, Cu was further doped in AgNi NWs to form AgNiCu NWs and regulate its surface oxide under long-term air exposure. Finally, it is demonstrated that the conductivity of AgNiCu NWs can acquire an improved tolerable temperature (over 240 °C) and prolonged high-temperature tolerance time (over 150 min) by finely regulating the doping content Cu, indicating an enhanced air-stable conductivity. The optimized AgNiCu NWs also achieve superior transparent conductivity as pure Ag NWs and high work function as AgNi NWs, which has been successfully applied in constructing an n-type photodiode with an effective rectification effect.