There were a large number of ionic liquids electrodeposition reported in the literature; but were still in the laboratory stage some problems in the practical application of electrodeposition remain such as easily reacted with moisture in the air (AlCl 3ionic liquid), high cost, and corrosive (dialkylimidazolium cation and , ionic liquid). In addition to the above shortcomings, low solubility of many metal salts in ionic liquids limits the practical application. In order to solve the problem of low solubility, [Bmim]Cl could be added [Bmim]PF 6, which could significantly increase the solubility of metal chlorides; this method could be commonly used in preparing metal electrochemical reduction of metal chlorides. Our study showed that adding cationic groups in hydroxyl ionic liquid could cause the good solubility of transition metal chlorides, such as CuCl 2. Complexation of hydroxyl functional group and transition metal ions increased solubility, resulting in a larger deposition current density and surface electrochemical reduction of copper nanoparticles deposited on the metal Ni. The electroreduction mechanism and behavior of CuCl 2in hydroxyl ionic liquid and the Cu nanoparticle formation mechanism were investigated based on a comparison between similar experiments in the ionic liquid.