Graphitic carbon nitride (g-C3N4) has shown promising potential application in photocatalytic production of hydrogen peroxide (H2O2) due to its suitable electronic band structure and facile preparation. Nevertheless, the ability of H2O2 production is limited by the unsatisfactory light utilization and the low specific surface area. In the present work, we developed a NaClO-assisted ammonia pyrolysis method to achieve the simultaneous introduction of sodium doping and cyano groups with nitrogen vacancies into the framework of g-C3N4 by the synergistic effect of Na+ intercalation and ClO− oxidation. Moreover, the easy removal of NaClO-derived NaCl can further increase the specific surface area and exposed active sites after water washing. All the features above are beneficial to extend the light absorption and improve the separation efficiency and redox ability of photo-generated electrons and holes over the optimal catalyst, which contribute to the high H2O2 yield of 415.5 μM within 4 h and excellent cyclic stability.