The study explores the use of a nickel-based catalyst supported by coal gangue for converting waste plastics into valuable products like hydrogen and carbon nanotubes. The research focused on the catalytic pyrolysis of polyethylene using the catalyst in a two-stage fixed bed reactor. Results indicated that the 15% Ni/CG catalyst showed peak performance at 750°C, achieving high hydrogen concentration, yield, and carbon nanotubes production. The catalyst also demonstrated good regeneration capabilities through gas-phase oxidation after multiple cycles. By enriching the catalyst surface with high-quality carbon nanotubes, the study highlights the potential of coal gangue as a support material for catalytic processes. Additionally, the mechanism of carbon nanotubes formation during catalytic decomposition was discussed, providing insights into the efficiency of the process and the quality of the resulting products.