The effects of anionic surfactant (sodium dodecyl sulfate, SDS) and cationic surfactant (cetyl trimethyl ammonium bromide, CTAB) on the coelectrodeposition of Ti-coated diamond-Ni composite plating are studied in this paper. The electrolytic deposition behaviour of nickel is investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results indicate that the diamond coated with Ti exhibits better infiltration when contact with Ni plating in contrast with that without Ti coating. The SDS with a concentration of 0.05 g/L inhibits the electrolytic deposition of Ni. While the CTAB with a concentration of 0.05 g/L promotes the transfer of Ni2 ions and accelerates the electrolytic deposition of Ni. The addition of SDS and CTAB refines the Ni coating and favours the evolution of hydrogen in the course of electrolytic deposition. Moreover,SDS and CTAB both decreases the numbers of pinhole and pitting in the coating.