Sustained silver (Ag) electroless deposition onto copper (Cu) surface was achieved from a simple and stable solution, which only containing silver salt, choline chloride (ChCl) and H2O, without using of catalyst and reductant.The mechanism of Ag deposition in ChCl-H2O solution was proven by ultra violet spectroscopy and cyclic voltammetry techniques.Through a study of the Ag coatings using atomic absorption spectroscopy, X-ray diffractometer and scanning electron microscope, we demonstrate that sustained deposition of Ag was achieved in ChCl-H2O solution with mole ratio higher than 1 ChCl ∶ 5 H2O and the calculated activation energy ofAg deposition was 13.0 kJ· mol-1.