In this paper, we report the effect of annealing on hybrid nanoflower like Cu(OH)2/CuO thin film prepared by simple and low-cost successive ionic layer adsorption and reaction (SILAR) method. As synthesized and annealed sample have been used for the structural characterization by using X-ray diffraction (XRD) analysis techniques. After finding pure phase of CuO sample, we have to use these electrodes for electrochemical supercapacitive properties, like cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS). Results exhibited that, CuO nanoflakes exhibit the higher value specific capacitance 476 F/g. Also, EIS studied to confirm lower ESR value, high power, performance, and excellent rate of CuO nanoflakes. Thus, present-day investigation effectively reports the applicability of facile and inexpensive SILAR method of synthesis of pure CuO nanostructure for the supercapacitor application.