Mo-Bi-S composite supported on carbon nanotubes (CNTs) was synthesized by hydrothermal method(Mo-Bi-S@CNTs). The effects of preparation temperature on the morphology, structure, and CO2 electrocatalytic performance of the catalysts were investigated. The results show that the Mo-Bi-S nanoparticles synthesized at 200 ℃ were smaller than others, about 10~15 nm in size and distributed uniformly on CNTs. At the same time, they showed better electrocatalytic performance in [NH2-emim]BF4-H2O (ω=40%) electrolyte. The Faraday conversion efficiency of methanol was as high as 63.0% over Mo-Bi-S@CNTs-200 ℃ at the potential -0.3 V vs.SCE. After 6 hours of continuous operation, the current density of the cell remained stable of about -13.5 mA/cm2. In summary, Mo-Bi-S@CNTs-200 ℃ was a kind of electrocatalytic CO2 reduction catalyst with high catalytic activity, methanol selectivity, and stability.