Electrocatalytic water splitting is an efficient method for hydrogen energy production. In alkaline water electrolysis, the hydrogen evolution reaction (HER) involves a kinetically sluggish two‐electron transfer process which limits the reaction rate. There are two reaction mechanisms for the alkaline water electrolysis, which are Volmer–Heyrovsky mechanism and Volmer–Tafel mechanism. Both mechanisms require the dissociation of hydrogen into H * . Pt has a weak ability to dissociate H 2 O but a strong ability to couple H * . Meanwhile, transition metal has a strong ability to dissociate H 2 O but a weak ability to couple H * . Therefore, coupling Pt and transition metal species into one catalytic system is an effective strategy to achieve efficient hydrogen evolution. Herein, a Co–Pt cluster–cluster heterogeneous electrocatalyst (Co n Pt n /C 3 N 4 ) for efficient alkaline hydrogen evolution is constructed. Specifically, Co n Pt n /C 3 N 4 exhibits excellent electrochemical performance such that it only requires an overpotential of 15 mV to achieve a current density of 10 mA cm −2 and 75 mV to achieve a current density of 100 mA cm −2 . It is proved that the Co–Pt cluster–cluster synergistic interaction in catalyst improves the electrochemical performance for HER.