The effects of gas, pressure and temperature on the production of amorphous carbon nanotubes were investigated using an arc discharging furnace at controlled temperature. Co/Ni alloy powder was used as catalyst. The discharge current was 80 A and voltage was 32 V. The optimal parameters were obtained: 600 temperature, hydrogen gas and 500 torr pressure. The productivity and purity of amorphous carbon nanotubes are 6.5 gram per hour and 80%, respectively. The diameter of the amorphous carbon nanotubes is about 7 20 nm.