Layer-by-layer self-assembly MoS2/C nanomaterials are constructed through the electrostatic adsorption between MoS2 nuclei with positive charge and C nuclei with negative charge using a facile one-step hydrothermal method. The layer-by-layer self-assembly MoS2/C catalysts with high exposure of catalytic hydrogenation active sites exhibit enhanced catalytic performance in phenanthrene hydrogenation.