The invention relates to a preparation method of a transition metal nickel oxide and cobalt oxide nanowire array, belonging to the technical field of nano materials. In the prior art, the chemical method is adopted to prepare a NiO nano material, but the prepared NiO nanowire material has disordered arrangement and does not form a good array morphology. The preparation method comprises the following steps of: using a tubular furnace, a vacuum tube and the like, placing a transition metal substrate in the vacuum tube, respectively placing transition metal choloride in two tubular containers with one respective closing end in equal weight, and placing the two tubular containers in the vacuum tube, wherein the opening ends of the tubular containers are relatively toward both side edges of the transition metal substrate; placing the vacuum tube in the tubular furnace, and starting a vacuum pump to vacuumize the cavity of the vacuum tube; increasing the temperature of the tubular furnace to 500-700 DEG C, and introducing O2/Ar mixed gas from an intake tube, wherein O2 accounts for 5-15% of mixed gas in volume; and continuing increasing the temperature to etching temperature, determining the etching temperature within the range of 900-980 DEG C, and maintaining for 10-30 min.