In this paper, we present a novel electroplating method for synthesis of carbon nanotubes (CNTs)-nickel (Ni) composite, and evaluate the mechanical property of the composite. CNTs are pretreated to have a positive charge on its surface and added into a Ni electroplating solution to form a CNTs-Ni composite electroplating suspension. The weight fraction of the CNT in the electroplated composite is 9.1 wt%, and the ultramiroindentation hardness is 13 GPa. The mechanical strengthening improvement is found in the composite in comparison with Ni film.