•A series of CoS2@MOF-derived hollow carbon spheres were prepared by solvothermal method.•The overpotential of 232 mV at a current density of 10 mA cm−2 was achieved by CoS2–600.•The synergistic effect between CoS2 and hollow carbon spheres was discussed. Electrocatalytic water splitting is a promising method for producing high-purity hydrogen. Metal-organic frameworks (MOFs) have recently emerged as unique electrocatalysts for overall water splitting. With their large specific surface area, high porosity, adjustable composition, and diversified structure, MOFs are widely used as precursors for preparing non-noble metal-based electrocatalysts. This paper presents the preparation of CoS2 particles loaded on carbon spheres derived from Co-MOF microspheres by calcination and sulfide reaction with sulfur. The optimized CoS2–600 particles demonstrate excellent OER and HER electrocatalytic performance in 1 M KOH solution. The MOF does not act as a catalyst, but rather adjusts the phase of the catalytic active material, changes the intermediate adsorbent, and increases the number of catalytic sites. The morphology and physical phases of the CoS2–600 particles were analyzed after cycling to identify the real active components during hydrogen and oxygen evolution.