NiS hollow spheres with controllable diameter sizes have been prepared in large scale by a simple method, where cyclohexylamine, as both solvent and reductant, successfully controlled the rate of releasing S2-. NiS nanoparticles were self-aggregated into hollow spheres around the in situ formed poly(N-vinyl-2-pyrrolidone) (PVP, M-w = 30,000) spherical micelles in the cyclohexylamine media. The as-obtained high-quality NiS hollow spheres with loosely packed nanoparticles would show interesting applications in optical device and lithium-ion battery.