The effect of magnetic field assisted heat-treatment on the field emission properties of metalized multi-walled carbon nanotubes (MWNTs) is investigated. The metalized MWNTs are prepared via an electroless plating method, and then the MWNTs/Ni cathodes are fabricated by screen printing. The morphology and composition of MWNTs/Ni were studied by transmission electron microscopy and energy dispersive X-ray detector, and the difference between MWNTs/Ni cathodes heat-treated with or without magnetic field was observed by scanning electron microscopy. The force of a single MWNT coated with Ni was simulated, and the results demonstrate that the magnetic field force could induce the rotation of MWNTs/Ni during magnetic field assisted heat-treatment. The field emission characteristics show that the MWNTs/Ni cathodes heat-treated with magnetic field has a low turn-on field of 0.80 Vm-1 and high field enhancement factor of 16068, which are attributed to the embossment of MWNTs/Ni from substrates under the magnetic field.