Metal　nanowires　show　promise　in　a　broad　range　of　applications　and　can　be　fabricated　via　a　number　of　methods,　such　as　vapor-liquid-solid　process　and　template-based　electrodeposition.　However,　the　synthesis　of　Al　nanowires　(NWs)　is　still　challenging　from　the　stable　alumina　substrate.　In　this　work,　the　Ni-catalyzed　fabrication　of　Al　NWs　has　been　realized　using　various　Al2O3　substrates.　The　growth　dynamics　of　Al　NWs　on　Ni/Al2O3　was　studied　using　in　situ　transmission　electron　microscopy　(TEM).　The　effect　of　alumina　structures,　compositions,　and　growth　temperature　were　investigated.　The　growth　of　Al　NWs　correlates　with　the　Na　addition　to　the　alumina　support.　Since　no　eutectic　mixture　of　nickel　aluminide　was　formed,　a　mechanism　of　Ni-catalyzed　reduction　of　Al2O3　for　Al　NWs　growth　has　been　proposed　instead　of　the　vapor-liquid-solid　mechanism.　The　key　insights　reported　here　are　not　restricted　to　Ni-catalyzed　Al　NWs　growth　but　can　be　extended　to　understanding　the　dynamic　change　and　catalytic　performance　of　Ni/Al2O3　under　working　conditions.