Abstract: To address the issues of easy deactivation, low graphitization degree of the product, and non-uniform tube diameter of Ni-based catalysts during the synthesis of multi-walled carbon nanotubes （MWCNTs） via methane cracking, a Mo-doped Ni-based alloy catalyst was fabricated by the coprecipitation method using layered double hydroxide （LDH） as the precursor. A series of characterization techniques including X-ray diffraction （XRD）, transmission electron microscopy （TEM）, energy-dispersive X-ray spectroscopy （EDS）, Raman spectroscopy, and scanning electron microscopy （SEM） were employed to characterize the phase composition and crystal structure, particle dispersion of the catalyst, as well as the microstructural features and performance of the as-synthesized MWCNT. Moreover, the effects of key reaction parameters including Mo doping content and reaction temperature on the catalytic performance for methane cracking and the preparation performance of MWCNT were investigated in a rotary furnace reactor. The results indicated that the active components of the catalyst prepared from the LDH precursor presented uniform dispersion; Mo doping significantly suppressed the deactivation of the catalyst and thus enhanced its catalytic performance for methane cracking. Specifically, at a reaction temperature of 650 ℃, the Ni_2.7Fe_0.3Mo_0.2@Al₂O₃ catalyst achieved a methane conversion rate of 75.65% within 1 h, which was remarkably higher than that of the Mo-free control sample （50.42%）. In addition, the as-obtained MWCNT product exhibited an improved graphitization degree with an I_G/I_D ratio of 0.93, an average tube diameter of 33.1 nm and a narrow diameter distribution ranging from 22.1 nm to 39.6 nm. The resistivity of the as-synthesized MWCNTs was measured to be 22.1 mΩ·cm under 20 MPa, which was evidently superior to that of the commercial MWCNT control sample （24.6 mΩ·cm）.