Cu-doped nickel oxide (NiO) thin films are prepared by electrochemical deposition technique from N, N-dimethylformamide (DMF) solutions. Morphology, structure, optical and electrochromic properties of the Cu-doped NiO films are investigated by means of scanning electron microscope (SEM), X-ray diffraction (XRD), ultraviolet-visible spectrophotometer (UV-vis), Fourier-transform infrared spectrometer(FTIR) and cyclic voltammetry (CV), respectively. Studies on the effects of Cu doping concentration, deposition potential and deposition time on the transmission properties of both the bleached state and colored state show that when CuNi =18, the film deposited under 3.5 V for 15 min exhibits the optimum electrochromic behavior with a max variation of transmittance (ΔTλ=560 nm) up to 78.7%. SEM images indicate the formation of nanorods. The films are formed with amorphous or short-range ordered NiO grains and a trace of face-centered cubic NixCu1-xO confirmed by XRD. Cu-doped NiO film also exhibits the fast response time as well as long cycle life.