Black Cu-Sn alloy coating was prepared from 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquids by electrodeposition method. The electrochemical behaviors of different electrodeposition systems were investigated by cyclic voltammetry. The micromorphology of the black coating was investigated by scanning electron microscopy (SEM) coupled with energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results showed that black coating was cypress leaf-like material. The electrochemical behavior in [BMIM]Cl-CuCl2 center dot 2H(2)O-SnCl2 center dot 2H(2)O ionic liquids showed the peak located at -0.5 V similar to -1.0 V belonged to the reduction peak of coppe-tin alloy co-deposition. The element compositions of coating were Cu and Sn, and the phase composition of the coating was Cu-13.7 Sn. center dot