Composition-uniform　Ni-Cu/Al2O3　alloy　catalysts　have　been　prepared　from　Ni-Cu-Al　hydrotalcite-like　compounds　(HTlcs)　and　tested　for　methane　decomposition　at　650　degrees　C.　The　catalysts　were　characterized　by　XRD,　XPS,　H-2　chemisorption,　H-2-TPR,　STEM-EDX,　SEM,　TEM,　and　Raman.　The　characterizations　reveal　that　calcination　of　Ni-Cu-Al　HTlcs　leads　to　Ni(Cu,Al)O　oxide　solid　solution,　both　nickel　and　copper　ions　being　homogeneously　distributed　in　HTlcs　as　well　as　in　Ni(Cu,Al)O,　and　upon　reduction　the　well-mixed　Cu2+/Ni2+　species　are　step-wise　reduced　to　form　composition-uniform　Ni-Cu　alloy　with　an　average　size　of　9.5-10.4　nm.　Alloying　Ni　with　an　appropriate　amount　of　Cu　remarkably　enhances　the　catalytic　life　and　carbon　yield.　The　highest　carbon　yield　of　132.9　g-C/g-cat　is　obtained　at　atomic　ratio　of　Ni:Cu　=　7:3,　which　is　about　78　times　that　of　the　Ni/Al2O3　counterpart.　Moreover,　carbon　morphology　is　changed　from　thin　CNTs　to　thick　fishbone-CNFs　and　platelet-CNFs　depending　on　the　copper　content.　Under　the　reaction　atmosphere,　Ni-Cu　alloy　is　sintered　to　large　particles　by　contact　with　methane.　It　is　suggested　that　Ni-Cu　alloying　favors　the　formation　of　large　alloy　particles,　which　inhibits　methane　dissociation　and　enhances　carbon　bulk　diffusion,　thus　facilitating　the　CNFs　growth　and　leading　to　a　significant　increase　of　carbon　yield.