Abstract: The opmplex oxides Ln_1-xSr_xMO₃ (Ln:rare earth elements.M:Co,Ni,Mn or their mixture), mixed with active carbon, were found to be promising as O₂ cathodic reduction catalysts with higher catalytic activity than either of them alone. The steady-state polarization curves of cathodic reduction of oxygen are composed of two Tafel lines with different slopes: b₁=-2.303RT/(1+α)F and b₂=-2.303RT/αF(α=0.5) for the low c. d.and higher c. d.region respectively. Experiments carried out at different temperatures showed that the system of Ln_1-xSr_xMO₃(10%)-active carbon has a higher catalytic activity for the electrochemical reduction of oxygen in comparison with that of silver(21.2%)-active carbon. The zinc-air cells in which the positive electrodes are made of Ln_1-xSr_x MO₃(10%)-C are found to have specific energy of 340 Wh/kg or 430 Wh/1 and goodshelf-life.