The invention belongs to the technical field of material synthesis and discloses a preparation method of a CoS nanoparticle/N-doped RGO composite material with a hydrogen evolution effect. According to the method, a precursor is synthesized with a simple one-step solvothermal method, and then the CoS nanoparticle/N-doped RGO composite material is generated through high-temperature calcination and used for improving hydrogen evolution performance under an acidic condition. The preparation method has the advantages that the method is environment-friendly, the cost is low, the preparation process is simple, large-scale industrial production of a prepared catalyst is facilitated, and the prepared catalyst has excellent electrocatalytic activity and good hydrogen evolution stability. Heterocyclic atoms N are introduced into CoS/RGO, a synergistic effect of geometric imperfections and heteroatoms is realized, so that adsorption free energy of a carbon material for hydrogen ions can be reduced, hydrogen evolution is better facilitated, and the electrochemical performance of CoS can be improved substantially.