Hydrogen from electrolysis cell driven by sustainable electricity is one of the most clean and renewable energy sources. The design and synthesis of efficient and robust noble-metal-free electrocatalyst for hydrogen evolution reaction (HER) are of paramount importance in modern society. Herein, we developed a simple two-step strategy to construct a new Ni/CoS heterostructure using carbonised (900 °C) filter paper (FP) as a precious metal-free electrocatalyst for hydrogen evolution reaction (HER) in alkaline media. The optimized electrocatalyst can achieve an ultralow overpotentials of 76 mV for HER at 10 mA cm in 1.0 M KOH. Moreover, it can be maintained a current density of 100 mA cm at 380 mV (vs. RHE) for 37 h. More importantly, experimental and theoretical calculations reveal that the remarkable enhancement of HER activity could be attributed to the synergistic effect of Ni and CoS that lead to the moderate hydrogen adsorption on Ni surface and improve the water dissociation at the interface of Ni/CoS. Our work paves a new pathway to design high-efficient electrocatalysts for massive hydrogen production.