The presence of nitrogen atoms in reduced graphene oxide (RGO) sheets considerably modulates their intrinsic physical and chemical properties to finally improve their electrochemical properties in electric double layer supercapacitors. However, this also accelerates the restacking phenomena of RGO, which results in a decreased active surface area and pore volume. To solve this problem, we fabricated para-phenylenediamine (p-PDA) functionalized nitrogen doped RGO (NRGO) to inhibit the restacking phenomenon and thus preserve the active surface area and pore volume via chemical bonding between RGO and p-PDA. Finally, we realized an impressive electrochemical performance through the synergistic effect of nitrogen doping and p-PDA functionalization.