The objectives of the present research are synthesizing three-dimensional (3D) nickel nanostructures and investigating their magnetic properties. Thus a template-free method was used to prepare 3D dandelion-like nickel nanostructures via reducing of nickel chloride with hydrazine hydrate in ethylene glycol solution at 100 ℃. The resulting Ni nanostructures were characterized by means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected-area electron diffraction (SAED). And the magnetic properties of the 3D Ni nanostructures were measured as well. Results indicated that solvothermal process could be successfully used to prepare 3D dandelion-like nanostruetures of Ni at a relatively mild temperature of 100 ℃. And the conclusions were made as follows: as-prepared Ni samples had obvious shape anisotropy and were composed of fine nanocrystallites, while they had significantly enhanced ferromagnetic properties than bulk Ni and Ni nanoparticles.