The low-cost electro-catalysts are very crucial for the lithium-ion oxygen battery electrodes. In this work porous reduced graphene oxide (rGO) was synthesized by the chemical methods and mixed with melamine to obtain rGO/graphitic-C3N4 (g-C3N4) composite which compose of 50% rGO and 50% g-C3N4. SEM, XRD and FTIR characterizations showed that the synthesized composite structure reflected most of the features of the rGO structure. The synthesized rGO/g-C3N4 composite was prepared as the cathode for the Li-ion-oxygen battery and its discharge/charge performance was determined. The composite cathode demonstrated a distinctive performance since g-C3N4 catalyzed both the oxygen reduction and oxygen evolution reactions during the discharging and charging. This work showed that rGO/g-C3N4 composite electrode was quite promising as the cost-effective cathode for the Li-ion-oxygen batteries.