MoS₂/CuS composite catalysts were successfully synthesized using a one-step hydrothermal method with sodium molybdate dihydrate, thiourea, oxalic acid, and copper nitrate trihydrate as raw materials. The hydrogen production performance of MoS₂/CuS prepared with different molar ratios of Mo to Cu precursors (n_Mo∶n_Cu) as cathodic catalysts was investigated in the two-chamber microbial electrolytic cell (MEC). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscope (TEM), linear scanning voltammetry (LSV), electrochemical impedance analysis (EIS), and cyclic voltammetry (CV) were used to characterize the synthesized catalysts for testing and analyzing the hydrogen-producing performance. The results showed that the hydrogen evolution performance of MoS₂/CuS-20% (n_Mo∶n_Cu=5∶1) was better than that of platinum (Pt) mesh, and the hydrogen production rate of MoS₂/CuS-20% as a cathode in MEC was (0.203 1±0.023 7) m_H2³·m^-3·d^-1 for 72 h at an applied voltage of 0.8 V, which was slightly higher than that of Pt mesh of (0.188 6±0.013 4) m_H2³·m^-3·d^-1. The addition of a certain amount of CuS not only regulates the electron transfer ability of MoS₂ but also increases the density of active sites.