The first aim of this study was to investigate the ZnO modification effect on the prussian blue (PB) films. A second aim of the study was to determine the decoration effect of multi walled carbon nanotube (MWCNT) on the PB-ZnO nanocomposite films which could be deposited by chemical bath. The electrochemical behaviour of PB films was systematically studied using ZnO-orZnO/MWCNT modification. Additionally, detailed optical properties of nanocomposite films were determined by UV-VIS, FTIR and Raman spectroscopy. Optical transparency was severely decreased by ZnO modification onto PB film but the decoration of MWCNTs did not change the optical transparency of film compared to PB film. PB, ZnO and MWCNT presence in the nanocomposite films were proven by FTIR spectrum. Stretching vibration peak of C=N shifted to short-wavelength for PB-ZnO nanocomposite films and same peak disappeared with MWCNT coating due to the structural distortion. ZnO modification and MWCNT coating affected the electrochemical properties due to the different factors such as OH-group effect in film growth process, Zn2+ substitution with Fe2+ site and interaction between ferricyanide ions and oxygen.