In this work, the electrochemical behavior and passivation of Cu-30Zn alloy in aqueous NaOH solutions was investigated using various electrochemical methods. Potentiodynamic polarization curves showed that increasing NaOH concentration leads to increase corrosion current densities. Mott-Schottky analysis indicated that the passive films displayed p-type semiconductive characteristics and the acceptor densities increased by increasing NaOH concentration, while the flat band potential decreased. Moreover, electrochemical impedance spectroscopy studies showed that the impedance value decreased by increasing NaOH concentration, due to increase in the Zn dissolution of Cu-30Zn alloy, which is consistent with the results of the polarization experiment and X-ray diffraction patterns.