In this work, the application potential of transition metal and P co-doped graphene-based SACs (TMP4) as the bifunctional ORR/OER electrocatalysts has been comprehensively explored by using first-principle calculations. Results demonstrate that the negative binding energies between TM and P4C can guarantee the stability of the structures of TMP4. Then, the bifunctional ORR/OER activity of TMP4 were evaluated, and the CoP4 structure, whose bifunctional catalytic activity are even better than that of Pt and IrO2 catalysts, exhibits the most promising bifunctional ORR and OER catalytic performances with the low overpotentials of 0.37 and 0.32 eV (the smallest ∆𝐸), respectively. Based on the scaling relation between OH*, O* and OOH*, we established the volcano plots to suggest the activity tendency of ORR and OER processes on TMP4, showing that CoP4 catalyst occupies the top owing to the moderate adsorption interaction between TMP4 and OER/ORR intermediates. In addition, the PDOS, d-band center (Ed) and work function were calculated to clarify the origin of highly reactive nature of TMP4. Furthermore, the AIMD simulation was conducted to evaluate and guarantee the thermodynamic stability of CoP4 catalyst. The present results theoretically accentuate that CoP4 is a promising electrocatalyst for ORR and OER with high activity and stability.