This study focuses on the development of the composite electrode materials for an aluminum-air battery and improving the oxygen reduction reaction (ORR) of the air electrode by matching alpha- and beta- manganese dioxide (MnO2) with poly-(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer. The catalyst powders of α-MnO2 and β-MnO2 are prepared by hydrothermal method with different precursors, while PEDOT conducting polymer is subsequently deposited on the screen-printed electrodes (MnO2/carbon paper) by oxidative chemical vapor deposition (oCVD). Material characteristics of prepared MnO2 powder and PEDOT layer are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman scattering spectroscopy. The half-cell polarization curve test is found to be strongly depended on the crystalline phases of MnO2. From experimental observations and a density functional theory (DFT) study, the conductivity of PEDOT/α-MnO2 is found to be higher than PEDOT/β-MnO2 contributed to structural effect mediated improvements in charge transfer. As a result, integrating the deposition of PEDOT on α-MnO2/carbon paper as composite cathode is suitable for the use in aluminum-air battery.