A hybrid of oxygen-defect-abundant Co3O4-x nanoparticles and graphene was successfully synthesized by a simple one-step laser irradiation method, and N atoms were introduced into the graphene by subsequent hydrothermal treatment. The Co3O4-x/NG exhibits remarkably enhanced OER and ORR catalytic performance compared to Co3O4/NG and a mixture of Co3O4-x and NG, which could be attributed to the oxygen vacancies and the synergistic effect of Co-N-C species. This study can offer a new way for the design and synthesis of OER/ORR bi-functional electrocatalyst.