Carbon based nanomaterials have attracted great attentions in the fields of electrocatalysis and photocatalysis. Here, we report our recent progress on photocatalytic hydrogen evolution of graphitic carbon nitride (g-C3N4) by introducing carbon based electrocatalyst as co-catalyst. Cobalt/nitrogen doped graphitic carbon (Co-NG) composite with tubular structure was synthesized by cobalt catalyzed carbonization and graphitization of urea under thermal treatment. Co-NG with strong interaction of cobalt and nitrogen doped graphitic carbon has shown low overpotential for electrocatalytic hydrogen evolution reaction. It was thus used as co-catalyst for graphitic carbon nitride (g-C3N4). Beside enhanced light absorption and reduced recombination of Co-NG/g-C3N4 heterostructure composite, high interfacial redox reaction activity of Co-NG was found. The photocatalytic hydrogen evolution activity of Co-NG/g-C3N4 was thus effectively improved.