Abstract: One-dimensional silicon nanostructures were synthesized via thermal evaporation technique using nickel catalyst. Effects of nickel catalyst and silicon substrate position on the formation of silicon nanostructure were studied extensively. Silicon powder that used as silicon source was evaporated at 900-1000°C for 1 h using tube furnace under controlled environment. The uncoated and nickel-coated silicon substrates were positioned at 3-12 cm from the silicon powder at downstream nitrogen gas flow. It was found that on the substrate without nickel catalyst have no traces of silicon nanostructures. However, on the nickel-coated silicon substrate obtained nanowires and needle-like nanostructures with various diameter and length. These results prove that nickel catalyst is playing an important role on the growth of silicon nanostructures on silicon substrate. Most of the grown one-dimensional silicon nanostructures are not in vertical alignment but bends to the certain direction. This bent-shaped formation might be due to the applied force of carrier gas flow during thermal evaporation. The nickel catalyst at the tip of silicon nanowires could be confirmed the growth mechanism of one-dimensional silicon nanostructures is similar to vapor-liquid-solid mechanism.