Carbon materials have drawn great attention in electrocatalytic water splitting with remarkable electronic conductivity and long-term durability. However, for pure carbon materials, it is difficult to obtain excellent electrocatalytic properties due to the inert potential of surface atoms and the lack of active centers in electrochemical reactions. Heteroatom-doping, which changes the charge and spin density of the carbon atoms around the doped atoms and thus increases the number of active sites, is regarded as an appealing way to enhance the electrocatalytic performances. Herein, a novel bifunctional Fe-Cu-N co-doped carbon catalyst was prepared through a facile hydrothermal-annealing strategy for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline solution. As demonstrated experimentally, high temperature induced nitrogen to transfer from decomposed g-C3N4 to carbon spheres, breaking inert atmosphere of graphite carbon surface and enlarging active surface area. Through regulating the ratio of Fe and Cu, as-prepared samples exhibited an enhanced water splitting capability. Electrochemical tests revealed that the catalyst with Fe-Cu co-doped enhanced electron conductivity and enlarged electrochemical active surface area (ESCA). As a result, a favorable catalytic water splitting performance was observed in Fe-Cu@CN3: overpotentials of 91 mV at 10 mA/cm2 and 362 mV at 10 mA/cm2 for catalyzing the HER and OER, respectively. This work gives a novel strategy for the design and fabrication of bifunctional carbon-based electrocatalysts.