Several composite catalysts were facilely fabricated by hydrothermal supporting CoSe2 on N, S dual-doped graphitic mesoporous carbon (SDGC) synthesized by pyrolyzing thiocarbamide and in-situ formed phenolic resin. The synthesized CoSe2/SDGC composites were characterized to have mesoporous structure distributed on the carbon matrix covered with the sphere like aggregates of CoSe2. Their electrocatalytic performances were evaluated by hydrogen evolution reaction (HER) in 0.5 M H2SO4. The results have shown that the as-prepared catalysts exhibited highly improved electrocatalytic activities for HER compared with the pristine CoSe2 and SDGC. Especially, the composite CoSe2/SDGC-60 with the optimized ratio of CoSe2 to SDGC has exhibited the highest electrocatalytic activity. The catalyst has obtained the lowest overpotential and Tafel slope of 203 mV (at 10 mA/cm(2)) and 58 mV/dec, respectively. It also showed impressive durability against 0.5 M H2SO4 and the electrocatalytic activity hardly decreased even after 5000 cycles. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.