(La,Ca)MnO₃ has been proposed as a candidate for the air electrode in a zinc-air battery, however it goes through a decomposition reaction in the presence of 6 KOH during cycling. In this work, we report the electrochemical properties of a nanocomposite, consisting of CaO nanoparticles, La₂O₃ nanorods, and MnO₂ nanotubes, supported on carbon nanotubes (CNTs). This nanocomposite exhibits a superior bi-functional activity towards oxygen reduction reaction and oxygen evolution reaction in a zinc-air battery with a discharge peak power density of ~203 mW cm^-2, a current density of ~150 mA cm^-2 at 1.0 V cell voltage, and an energy density of ~725 mAh g^-1., all of which are better than these of commercial Pt/C and IrO₂/C. a long life test for power generation is demonstrated by replacing a total of 30th pieces of Zn plates and electrolyte. Furthermore, this rechargeable ZAB exhibits a small charge–discharge voltage polarization (~0.77 V) and excellent stability (534 cycles) cycling at 10 mA cm^-2.