The invention discloses high-precision nickel-chromium/copper-nickel thermocouple alloy wires and a production process thereof. A nickel-chromium thermocouple alloy wire comprises the components of chromium, cobalt, silicon, calcium, yttrium, carbon, sulfur, iron, nickel and a misch metal; a copper-nickel thermocouple alloy wire comprises the components of nickel, manganese, magnesium, calcium, carbon, sulfur and copper; and the process comprises the following steps of: (a), preparing raw materials; (b), performing vacuum melting; (c), performing hot rolling; (d), performing wire drawing and annealing; and (e), testing finished products, packaging the finished products to leave factory. The nickel-chromium/copper-nickel thermocouple alloy wires, which are produced according to a unique product formula and by the unique production process, can reach a high-precision I-grade level.