The design and construction of electrocatalysts with high efficiency, low cost and large current output suitable for industrial hydrogen production is the current development trend for water electrolysis. Herein, a lattice‐confined in situ reduction effect of the 3D crystalline fullerene network (CFN) is developed to trap Ru nanoparticle (NP) and single atom (SA) via a solvothermal‐pyrolysis process. The optimized product (RuNP‐RuSA@CFN‐800) exhibits outstanding electrocatalytic performance for alkaline hydrogen evolution reactions. To deliver a current density of 10 mA cm−2, the RuNP‐RuSA@CFN‐800 merely required an overpotential of 33 mV, along with a robust electrocatalytic durability for 1400 h. Even at large current densities of 500 and 1000 mA cm−2, the overpotentials are only 154 and 251 mV, respectively. Density function theorey calculation results indicated that the electronic synergetic effect between Ru NP and SA enable to regulate the charge distribution of RuNP‐RuSA@CFN‐800 and reduce the Gibbs free energy of intermediate species for water dissociation process, thereby accelerating the hydrogen evolution process. Moreover, the robust CFN matrix render this strategy patulous to other transition metals, e.g., Cu, Ni, and Co. The present study provides a new clue for the construction of novel electrocatalyst in the field of energy storage and conversion.