We report a facile aqueous-phase synthetic route to vine-like copper sulfide (CuS) nanofibers prepared by reacting elemental sulfur with Cu+ -branched polyethyleneimine (BPEI) complex obtained by the reaction of Cu2+ with ascorbic acid in the presence of BPEI. By controlling the concentration of BPEI, we could easily control the morphology of CuS from nanofibers to hollow nanoparticles. We also found that concentration of BPEI and the presence of halide anion would play important roles in the formation of vine-like CuS nanofibers. (C) 2016 Elsevier B.V. All rights reserved.