A novel facile route with the features of low-energy consumption and cheap nontoxic source materials was designed to prepare nickel-based metals such as Ni and FeNi and carbon core/shell (Ni/C and FeNi/C) nanostructures at room temperature and ambient pressure. The Ni/C and FeNi/C core/shell nanostructures were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrometry (EDX), Raman spectroscopy, infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The surfaces of nickel-based metal/C, being abundant in organic functional groups such as –OH and –COOH, could be easily loaded with biomolecules such as tyrosine, which may be used in clinic diagnostics, molecular biology, bioengineering, and catalysis by loading with other functional molecules (e.g. enzymes, antigens). The magnetic properties and oxidative resistance of Ni/C core/shell nanostructures have been investigated by vibrating sample magnetometry (VSM). It was found that the Ni/C core/shell nanostructures showed excellent magnetic properties compared with those of Ni/C obtained by other methods and had high stability. The present route may give researchers more choices for preparing other Ni-based metal/C nanostructures.