Silicon nanowires are a kind of promising negative electrode material for lithium-ion batteries. However, the existing production technologies can hardly meet the demands of silicon nanowires in quality and production ability. In this paper, silicon nanowires are successfully prepared by molten salt electrolysis in a pilot-plant. The pilot-plant was successfully operated for 14 months with a current efficiency of 80.3% and an electrolysis energy consumption of 12.8 kW h/kg-Si. The obtained silicon nanowires as a negative electrode material show a specific discharge capacity of 3095 mA h/g and a coulombic efficiency of 89.7% in the first charge-discharge cycle at a rate of 0.1 C in coin-type cell tests and a capacity retention of 83.4% after 250 cycles at a rate of 1 C in pouch cell tests when mixed with graphite.