The invention discloses a preparation method and a catalytic application of a supported type high-dispersion 
nickel-based 
alloy catalyst. The preparation method comprises the following steps: by virtue of an in-situ growth method, supporting Ni, M (M=Co, Zn, Cu, Fe, Cr and the like) 
metal in the form of 
hydrotalcite on the surface of a 
microsphere-form gamma-Al2O3 carrier with grain size of 20-40 meshes and in a duct of the 
microsphere-form gamma-Al2O3 carrier, namely growing lamellar precursor LDHs containing Ni and M 
metal ions outside and inside a Al2O3 particle to form supported type high-dispersion distribution, converting the lamellar precursor LDHs into a corresponding composite 
metal oxide by 
drying and 
roasting at high temperature, and reducing the composite metal 
oxide to obtain the supported type high-dispersion 
nickel-based 
alloy catalyst with NiM distributed on the outer surface and in the duct of the carrier particle. The supported type high-dispersion 
nickel-based 
alloy catalyst is applied to first selective 
hydrogenation reaction of cracked 
gasoline, so that the conversion rate, the selectivity and the stability of the catalyst can be effectively improved; and moreover, the supported type high-dispersion nickel-based 
alloy catalyst can be used for 
methane reforming, and catalyzing reaction of preparing low-carbon 
hydrocarbon and 
alcohol by virtue of CO and CO2 hydrogenation.