In this work, a fascinating nanocomposite based on manganese-cobalt sulfide (MnS/Co3S4) wrapped by electrochemically reduced graphene oxide (ERGO) has been successfully synthesized on the surface of a glassy carbon electrode (GCE) by a facile hydrothermal assisted electrochemical reduction method. The modified electrode was fully characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The morphological results illustrate that MnS/Co3S4 are embedded in the ERGO layers, resulting in a rough surface and three-dimensional (3D) microstructure. The as-synthesized MnS/Co3S4-ERGO/GCE displays distinctly enhanced electrocatalytic activity for vanillin oxidation in comparison with that of the ERGO/GCE and MnS/Co3S4/GCE. Therefore, the MnS/Co3S4-ERGO/GCE can be used as an effective electrochemical sensing platform for the sensitive determination of vanillin, and the fabricated sensor displays a wide linear range of 0.02−1.00 mmol/L and 1.0−40.0 mmol/L, low detection limit of 4.0 nmol/L and satisfactory recoveries between 98.0% and 102.8%.