By using the monolayer graphene grown by chemical vapor deposition (CVD) as the conductive electrode and ammonium tetrathiomolybdate aqueous solution as the electrolyte, the vertical heterojunctions of molybdenum disulfide-graphene (MoS2/graphene) were synthesized by electrochemical deposition method. The synthesized MoS2/graphene vertical heterojunction was annealed by chemical vapor deposition(CVD) system under the hydrogen and argon atmosphere. The Raman spectroscopy (Raman), X-ray diffraction (XRD), scanning electron microscope (SEM), and atomic force microscope (AFM) were used to systematically analyze the material composition, surface morphology, and thickness of the resulting MoS2/graphene vertical heterojunctions. This simple, environment-friendly, and low-cost method for synthesizing large-area MoS/graphene vertical heterojunctions has universal applicability, which opens a new way for the synthesis of other vertical heterojunctions.